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1

Phenomenological model of cavitation erosion of nitrogen ion implanted HIPed Stellite 6

Szala Mirosław

Advances in Materials Science

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2023

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Vol. 23, nr 1(75)

98--109

EN

Stellites are a group of Co-Cr-C-W/Mo-containing alloys showing outstanding behavior under cavitation erosion (CE) operational conditions. The process of ion implantation can improve the CE resistance of metal alloys. This work presents the elaborated original phenomenological model of CE of nitrogen ion implanted HIP-consolidated (Hot Isostatically Pressed) cobalt alloy grade Stellite 6. The ultrasonic vibratory test rig was used for CE testing. The nitrogen ion implantation with 120 keV and fluence of 5 × 1016 N+/cm−2 improves HIPed Stellite 6 cavitation erosion resistance two times. Ion-implanted HIPed Stellite 6 has more than ten times higher CE resistance than the reference AISI 304 stainless steel sample. Comparative analysis of AFM, SEM and XRD results done at different test intervals reveals the kinetic of CE process. The model includes the surface roughness development and clarifies the meaning of cobalt-based matrix phase transformations under the nitrogen ion implantation and cavitation loads. Ion implantation modifies the cavitation erosion mechanisms of HIPed Stellite 6. The CE of unimplanted alloy starts on material loss initiated at the carbides/matrix interfaces. Deterioration starts with cobalt matrix plastic deformation, weakening the carbides restraint in the metallic matrix. Then, the cobalt-based matrix and further hard carbides are removed. Finally, a deformed cobalt matrix undergoes cracking, accelerating material removal and formation of pits and craters' growth. The nitrogen ion implantation facilitates ɛ (hcp—hexagonal close-packed)) → γ (fcc—face-centered cubic) phase transformation, which further is reversed due to cavitation loads, i.e., CE induces the γ → ɛ martensitic phase transformation of the cobalt-based matrix. This phenomenon successfully limits carbide removal by consuming the cavitation loads for martensitic transformation at the initial stages of erosion. The CE incubation stage for ion implanted HIPed Stellite 6 lasts longer than for unimplanted due to the higher initial content of γ phase. Moreover, this phase slows the erosion rate by restraining carbides in cobalt-based matrix, facilitating strain-induced martensitic transformation and preventing the surface from severe material loss.

2

The Impact of Material Selection on Durability of Exhaust Valve Faces of a Ship Engine – A Case Study

Smoleńska Hanna, Kończewicz Włodzimierz, Bazychowska Sylwia

Advances in Science and Technology. Research Journal

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2020

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Vol. 14, no 3

165--174

EN

Two alloys were used in order to extend the service life of marine engine exhaust valve head. Layers of cobalt base alloys were made of the powders with chemical composition as follow: the layer marked L12; C-1.55%; Si-1.21%; Cr-29.7%; W-9%; Ni-2%; Mo<0.01%; Fe-1.7%; Co-54.83% and the layer marked N; C-1.45%; Co-38.9%; Cr24.13%; Ni-10.43%; W-8.75%; Fe-7.64%; Mo-7.56%; Si-2.59%. Base metal was valve steel after heat treatment. It was consisted of: C-0,374%; Cr-9,34%; Mn-0.402%; Ni-0.344%; Si-2.46%; Mo-0.822%; P-0.0162%; S-0.001%. Layers on the valve faces were produced by laser cladding using the HPDL ROFIN DL020 laser. Grinding treatment is a very popular form of regeneration of seat and valve plug adhesions. Properly performed grinding operation ensures dimensional and shape accuracy of the surface from 7 to 5 accuracy class and surface roughness Ra not less than 0.16 μm, depending on the object and method of grinding. The 75H and 150S types are a significantly simplified form of valve plug face grinders. Finishing treatment was carried out with a Chris-Marine AB75H sander on a sanding stand equipped with a compressed air system - the stand was designed by the author. The sander has been set up to the surface of the valve stem so that the grinding angle of the valve faces is 30°+10°. A flat grinding wheel T1CRA54–K was used for machining. The plunge feed was 0.01 mm/rev. The thickness of the welded layer after grinding was 1.2 mm. Both valves were installed in the ship’s engine and were used in real life. After 2000 hours of operation, the valve marked N was damaged. The valve marked L12 showed no damage and was in operation for the next 1000 hours.

3

Comparing of Microhardness of the Stellite 6 Cobalt Alloy Implanted with 175 keV Mn+ Ions and 120 keV N+ Ions

Kamiński Mariusz, Budzyński Piotr, Szala Mirosław, Turek Marcin

Advances in Science and Technology. Research Journal

|

2019

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Vol. 13, no 3

179--185

EN

Nowadays, high-precision machines require lightweight materials with very high strength. Ion implantation is used to improve the mechanical strength of the material. A further paper presents the influence of manganese and nitrogen ion implantation on changes of microhardness of the surface layer of cobalt alloy. Samples were analyzed with the SEM-EDS Phenom ProX microscope. Microhardness was assessed with the Vickers method, and the loads of 1 gf (0.00981 N) and 5 gf (0.049 N) was applied using a FM-800 from Future-Tech microhardness meter. At a load of 1 gf, the penetration depth of the implanted specimens was reached not exceeding 0.5 um. At this depth, all samples showed an increase in microhardness compared to the unimplanted sample. The highest increase in microhardness was achieved after implantation of Mn ions with dose D=1∙1017 Mn+/cm2 and energy E=175 keV. The increased load on the indenter to 5 gf reduced the microhardness differences between implanted and unimplanted samples.

4

The Effect of Atomic Layer Deposition of ZrO2 on the Physicochemical Properties of Cobalt based Alloys Intended for Prosthetic Dentistry

Ziębowicz A., Woźniak A., Ziębowicz B., Kosiel K., Chladek G.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 3

1077--1082

EN

The paper presents the effect of ZrO2 layer deposition by the ALD process on the physicochemical properties of cobalt-based alloys (Realloy C and EOS CoCr SP2) intended for application in prosthetic dentistry. The paper shows the results of the surface roughness measurements made by the AFM method as well as the wettability and free surface energy measurements. Additionally, potentiodynamic tests of pitting corrosion resistance and electrochemical impedance spectroscopy in a solution of artificial saliva were carried out. Tests were carried out on the samples in the initial state and after surface modification with the ZrO2 layer. Based on these results, the usefulness (e.g. enhancement of corrosion resistance and biocompatibility) of the proposed ZrO2 layer on the cobalt alloys was assessed.

5

Influence of Internal Scrap on Mechanical Properties of Selected Cobalt Alloys

Dęsoł B., Zapała R., Pałka P.

Journal of Casting & Materials Engineering

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2017

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Vol. 1, no. 3

59--63

EN

This paper presents the results of mechanical tests carried out on two different commercially available cobalt alloys applied in dental prosthetics for the production of frame dentures. The test samples were obtained by the method of investment casting using as a charge pure primary materials and pure primary materials mixed with various additions of process scrap (25, 50, and 75%). The tests showed that the alloys could not reach the mechanical properties reported by the manufacturer in either case. In the case of the alloy without the addition of tantalum, the general conclusion was that both the plastic and strength properties decreased with increasing amounts of the introduced process scrap. The mechanical properties (mainly elongation) of the alloy containing Ta reached the highest values in the samples containing 75% of the process scrap. Examinations of fractures carried out by SEM have revealed their varied character – ductile or transcrystalline. All of the samples tested showed the presence of dendrites and solidification areas, with shrinkage porosity occurring in the internal sample zones.

6

Tribological properties of Stellite 6 cobalt alloy implanted with nitrogen ions determined in the tests conducted in engine fuel atmosphere

Kamiński M., Budzyński P.

Advances in Science and Technology. Research Journal

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2017

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Vol. 11, no 4

215--219

EN

The influence of nitrogen ion implantation on the tribological properties of Stellite 6 cobalt alloy was investigated. The tribological tests were conducted using a pin / ball on disc in the atmosphere of engine fuels. In the study, cobalt alloy was implanted with 60 keV nitrogen ions at the fluence of 1∙1016 and 5∙1016 N+/cm2. The wear trace was measured using the Form Talysurf Intra Taylor Hobson profilometer. The results demonstrate that nitrogen ion implantation affects the friction coefficient and wear. The effect of nitrogen ion implantation depends on the environment in which the tribological test is carried out, the sample temperature and the presence of friction products in the friction node.

7

Electrochemical characteristics of a cobalt alloy with a protective passive layer

Reimann Ł.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 3

1283--1290

EN

The aim of this study was to assess the quality of the passive layer formed on the surface of a CoCr alloy used on dentures to see the effect on resistance to pitting corrosion and electrochemical parameters. Studies were performed using on potentiodynamic tests and electrochemical impedance spectroscopy. The passive layer was formed spontaneously and by electrochemical method on samples after casting and after simulation porcelain firing on metal. Samples of the passivation electrochemical characterized by the improvement in corrosion resistance. Prolonging the passivation time from one to 24 hours and increasing the potential value from 0 to 200 mV improved the quality of the passive layer and all characteristics of electrochemical parameters.

8

Microstructure and Functional Properties of Prosthetic Cobalt Alloys CoCrW

Nadolski M., Golański G., Klimas J., Szota M., Szymański J.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 3A

1999--2003

EN

The material subject to investigation was two commercial alloys of cobalt CoCrW (No. 27 and 28) used in prosthodontics. The scope of research included performing an analysis of microstructure and functional properties (microhardness, wear resistance and corrosion resistance), as well as dilatometric tests. The examined alloys were characterized by diverse properties, which was considerably influenced by the morphology of precipitates in these materials. Alloy No. 27 has a higher corrosion resistance, whereas alloy No. 28 shows higher microhardness, better wear resistance and higher coefficient of linear expansion. Lower value of the expansion coefficient indicates less probability of initiation of a crack in the facing ceramic material.

PL

Badaniu poddano dwa komercyjne stopy kobaltu CoCrW (nr 27 i 28) stosowane w protetyce stomatologicznej. Zakres badań obejmował przeprowadzenie analizy mikrostrukturalnej, właściwości użytkowych (mikrotwardość, odporność na ścieranie i odporność korozyjna) oraz badania dylatometryczne. Badane stopy charakteryzowały się zróżnicowanymi właściwościami na co zasadniczy wpływ miała morfologia wydzieleń w tych materiałach. Stop nr 27 posiada wyższą odporność korozyjną natomiast stop nr 28 wykazuje: wyższą mikrotwardość, lepszą odporność na ścieranie oraz niższy współczynnik rozszerzalności liniowej. Niższa wartość współczynnika rozszerzalności liniowej wskazuje na mniejsze prawdopodobieństwo inicjacji pęknięcia licującego materiału ceramicznego.

9

The Influence of Remelting on the Quality of Prosthetic Cobalt Alloys

Nadolski M., Łągiewka M., Konopka Z., Zyska A., Golański G.

Archives of Foundry Engineering

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2015

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Vol. 15, iss. 3 spec.

53--58

EN

A commercial cobalt alloy applied in dental prosthetics was investigated. The scope of the work included the microstructure analysis, performance examination (tensile strength, microhardness, corrosion resistance), and dilatometric examination. The investigated alloy after a single remelting was characterised by higher tensile strength and hardness. There were not found the definite results with regard to the corrosion resistance of the examined materials. No significant change occurred in the coefficient of thermal expansion.

10

Struktura i własności materiałów kompozytowych magnetycznie miękkich o osnowie silikonowej wzmacnianych nanokrystalicznymi proszkami stopu kobaltu

Konieczny J.

Przetwórstwo Tworzyw

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2014

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[R.] 20, nr 2 (158)

182--186

PL

W artykule przedstawiono wyniki badań mikrostruktury, własności mechanicznych i magnetycznych materiałów kompozytowych, magnetycznie miękkich o osnowie silikonowej. Proszki metalowe otrzymano w wyniku mielenia taśm metalowych o strukturze amorficznej oraz nanokrystalicznej ze stopu Co68Fe4Mo1B13,5Si13,5. Wykazano, że na własności mechaniczne jak i fizyczne bardzo silnie oddziałuje udział metalowego proszku.

EN

The article presents the investigation results of microstructure, mechanical and magnetic properties of soft magnetic composite materials with silicone matrix. Metal particles obtained by high energy ball milling of the metal ribbons of amorphous and nano-crystalline structure of the alloy Co63Fe4Mo1B13,5Si13,5. It was shown that the mechanical properties as well as physical influences strongly the powder metal part.

11

Osadzanie elektroforetyczne polimerowych powłok chitozanu na biomateriałach metalowych

Jugowiec D., Radziszewska A., Kot M., Moskalewicz T.

Engineering of Biomaterials

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2014

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Vol. 17, no. 128-129

16--19

PL

Powłokę chitozanu osadzono metodą elektroforezy na stopie tytanu Ti13Zr13Nb i stopie kobaltu Co28Cr-5Mo. W obecnej pracy skoncentrowano się głównie na doborze parametrów osadzania elektroforetycznego w celu otrzymania jednorodnych i ciągłych powłok chitozanu na biomateriałach metalowych. Stwierdzono, że jednorodność wytworzonych powłok istotnie zależała od rodzaju zastosowanego roztworu i parametrów osadzania. Mikrostrukturę materiałów podłoży oraz powłok zbadano za pomocą mikroskopii świetlnej oraz skaningowej- i transmisyjnej mikroskopii elektronowej. Zmierzono twardość i moduł Younga materiałów podłoży. Wykonano badania przyczepności powłok do podłoży stopu tytanu i stopu kobaltu.

EN

A chitosan coatings were electrophoretically deposited (EPD) on the Ti13Zr13Nb and Co28Cr5Mo alloys. The main aim of this work was to find optimal EPD parameters to obtain homogeneous and continuous coating on metallic biomaterials. It was found that the homogeneity of the as-deposited chitosan coatings on the substrate materials is highly dependent on chosen solution and EPD parameters. The microstructure of the substrate materials and coatings were investigated by light microscopy as well as scanning- and transmission electron microscopy. The hardness and Young’s modulus of the alloys as well as adhesion of chitosan coatings to the substrate materials were investigated.

12

Wpływ technologii wytwarzania na właściwości materiałowe stopu kobaltu wykorzystywanego w protetyce dentystycznej

Litwinko M., Grądzka-Dahlke M.

Aktualne Problemy Biomechaniki

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2014

|

z. 8

99--102

PL

Jednym z etapów w procesie powstawania protetycznego uzupełnienia dentystycznego jest realizacja zaprojektowanego kształtu protezy w tworzywie metalowym. Jest krokiem istotnym a zarazem narażonym na wiele niepowodzeń. W artykule przedstawiono porównanie dwóch metod wykonawstwa techniki dentystycznej: tradycyjnego odlewania oraz nowoczesnej SLM. Badaniom poddano protetyczny stop kobaltu w postaci prostopadłościennych próbek.

EN

One of the stages in the process of restoration of dental prostheses is the shape which was designed to achieve a complement in the metal. It is an important step and exposed to many setbacks. The article gives a comparison of two methods of dental technology: traditional casting and modern SLM. The test was in the form of a cobalt alloy prosthetic square bales samples.

13

Influence the heat treatment of two base metal alloys used on dental prosthesis on corrosion resistance

Reimann Ł., Dobrzański L.A., Nieradka B., Kusy M., Riedlmajer R.

Journal of Achievements in Materials and Manufacturing Engineering

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2013

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Vol. 57, nr 2

83--90

EN

Purpose: The goal of the study is to try find the influence of the heat treatment on the corrosion resistance of two base cobalt alloys used on dental prosthesis. Design/methodology/approach: The investigation was choosen two base cobalt alloys: Remanium 2000+ (Dentaurum) and Wirobond LFC (Bego). Corrosion resistance test were carried out at room temperature and use of the Potentiostat IPS AJ PGU system for electrochemical tests. The examination use of water center which simulated artificial saliva environment. The evaluation of pitting corrosion was realized by recording of anodic polarization curves with use the potentiodynamic methods. Structure observation was made after surface preparation by light microscope. Findings: Research cobalt alloys are characterized by a dendritic crystals in structure. For both cobalt alloys increasing the time of age hardening effect on growth of the corrosion resistance, especially to increase the potential for pitting initiation. Research limitations/implications: The research was carried out on samples, not on final elements. Practical implications: The research material is used on dentures, so it must characterize the corrosion resistance. Results of this work make up an information on what heat treatment parameters may be pay attention for two base cobalt alloys: Remanium 2000+ (Dentaurum) and Wirobond LFC (Bego). Originality/value: The paper presents influence the heat treatment of two base metal alloys used on dental prosthesis on corrosion resistance.

14

Zachowanie korozyjne stopów kobaltu w roztworze sztucznej śliny

Loch J., Krawiec H.

Archives of Foundry Engineering

|

2013

|

Vol. 13, iss. 3 spec.

101--106

PL

Stopy kobaltu są materiałami wykorzystywanymi w medycynie oraz stomatologii ze względu na swoje idealne połączenie dobrych właściwości wytrzymałościowych, korozyjnych oraz biokompatybilność. Obecnie stopy kobaltu są jednymi z najbardziej atrakcyjnych materiałów metalowych, używanych do wyrobu implantów w tym: sztucznych stawów biodrowych, kolanowych, dysków miedzykręgowych, śrub zabezpieczających złamania. W stomatologii wykonuje się z nich wszelkiego rodzaju wkręty, stanowiące podstawę do przytwierdzania zębowych protez ceramicznych. Ze względu na powszechne wykorzystanie stopów kobaltu w stomatologii, w pracy podjęto badania elektrochemiczne wybranych stopów kobaltu: Co-Cr-Mo i Co-Cr-W, których celem było określenie właściwości korozyjnych podczas ekspozycji w fizjologicznym roztworze sztucznej śliny, w temperaturze 37 °C, pH = 8,3 i swobodnym dostępie tlenu.

EN

Cobalt alloys are used in medicine and dentistry due to perfect combination of their high strength, corrosion resistance and biocompatibility. Currently, cobalt alloys are among the most attractive metallic materials used to manufacture such implants as artificial hip joints, knee joints, intervertebral discs, screws securing the fracture. All kinds of screws used in dentistry for basic fixing of ceramic dental prostheses are made from cobalt alloys. Widespread use of cobalt alloys in dentistry is the reason for electrochemical research on selected cobalt alloys (Co-Cr-Mo and Co-Cr-W). The aim of the research was to determine the corrosion when the alloy is exposed to physiological artificial saliva solution at the temperature of 37 °C, pH = 8.3 and in aerated solution.

15

Natryskiwanie detonacyjne powłok WC-Co na spieki kobaltowe

Borowiecka-Jamrozek J

Mechanik

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2012

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R. 85, nr 8-9

766--768

EN

A new method of manufacture of the metallic/diamond sandwich segments has been developed consisting in application of homogenous WC/Co coatings on the segment side facets by means of the gas detonation method.

PL

Opracowano nową metodę wytwarzania segmentów metaliczno-diamentowych typu sandwich, polegającą na nałożeniu na boczne powierzchnie segmentów jednorodnych powłok WC-Co metodą gazodetonacyjną, co spowoduje wytworzenie warstwy powierzchniowej o podwyższonej odporności na zużycie ścierne, które powinno zapewnić siodłowy profil zużycia segmentów podczas pracy piły. Uzyskane powłoki badano przez: obserwację mikrostruktury, analizę punktową, liniową za pomocą mikroskopu skaningowego, analizę składu fazowego. Wykonano pomiary mikrotwardości, badanie przyczepności powłok do podłoża, badanie odporności powłok na zużycie ścierne.

16

Niestabilność mechaniczna stopu kobaltu rejestrowana w próbie jednoosiowego rozciągania

Jeleńkowski J., Marchlewski P.

Obróbka Metalu

|

2011

|

nr 2

56-88

PL

Stopy na osnowie kobaltu Co-Cr-W-Ni wyróżniają się wysoką odpornością korozyjną, wysoką wytrzymałością przy statycznych i cyklicznych obciążeniach, odpornością na plastyczne odkształcenia przy krótkotrwałych przeciążeniach i odpornością na zużycie przez tarcie. Cechy te powodują, że są one stosowane na specjalne urządzenia do pracy w temperaturach od kriogenicznych do 400°C, a z powłoką Zr02 również do pracy przy temperaturach bliskich 1000°C

17

Metallographic analysis of selected cobalt-based alloys with carbon additive

Woźna A.

Aktualne Problemy Biomechaniki

|

2011

|

z. 5

177--184

EN

In this paper an analysis of the microstructure of cobalt-based alloys used for implants with different chemical composition was held. Metallographic analysis was conducted using the methods of light microscopy and scanning electron microscopy. Characterization and description of the phases occurring in the investigated alloys was carried out using X-ray microanalysis, X-ray diffraction analysis and hardness measurements. The aim of this study was to determine the nature of the structure, chemical composition and its selected properties that affect their use application.

18

Materiały stopowe kobalt-pallad

Zieliński M.

LAB Laboratoria, Aparatura, Badania

|

2010

|

R. 15, nr 2

14-18

19

Elektrochemiczna redukcja stopów kobalt-pallad

Zieliński M.

LAB Laboratoria, Aparatura, Badania

|

2010

|

R. 15, nr 1

11-14

20

Study on structures and properties of the laser cladding exhaust valve after service

Kończewicz W., Krużycki P., Smoleńska H.

Journal of KONES

|

2010

|

Vol. 17, No. 3

211-216

EN

The cobalt base laser cladding layers which were built up on the exhaust valve head face of the heavy loaded marine diesel engine have been investigated. The valve head with cladded face were served successfully for 3000 hours in the engine of the Dar Młodzieży. After removing from the valve head from the cylinder head the face surface were fully inspected. The surface topography and roughness were evaluated. Microstructure on the cross section of the clad layer were analyzed using Scanning Electron Microscope (SEM) equipped with energy dispersive spectroscopy (EDS. Also microhardness of the clad layer was measured. The service conditions resulted with the formation of the scale which had different thickness and tended to cracking and spalling. The microstructure of the clad layers after service did not demonstrated serious degradation process. The decrease of the hardness numbers was observed but still clad layer presented higher hardness than steel base. This type of clad layer underwent intensive laboratory examinations which contained oxidation experiments at different temperatures and corrosion in exhaust gases, long time exposition in laboratory engine and in the end 3000 hours successfully service on the ship. After such experience laser cladding cobalt base layers may be recommended as a useful solutionfor both prolongs of the service life and a method of the regeneration of the slightly used valve heads is suitable for practical applications.