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Właściwości powłok DLC z podwarstwami na bazie chromu zastosowanych na narzędziach ze stali szybkotnącej do obróbki drewna

Pancielejko M., Czyżniewski A., Gilewicz A., Zavaleyev V.

Inżynieria Materiałowa

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2014

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Vol. 35, nr 6

535--539

PL

W artykule przedstawiono wyniki badań właściwości powłok z zewnętrzną warstwą DLC (Diamond-Like Carbon) oraz trzema typami podwarstwy na bazie chromu: Cr/DLC, Cr/CrN/Cr/DLC oraz Cr/(CrN/CrCN)/Cr/DLC. Przedstawiono również wyniki badań trwałości i mechanizmów zużycia ostrzy noży strugarskich ze stali szybkotnącej pokrytych tymi powłokami. Podwarstwy na bazie chromu wytwarzano metodą katodowego odparowania łukowego (CVA), a warstwę DLC metodą zmodyfikowanego katodowego odparowania łukowego (MCVA). Powłoki DLC charakteryzują się dużą twardością (ok. 34 GPa) oraz dobrą adhezją. W próbie zarysowania powłoki Cr/DLC wykazują największą adhezję (siła krytyczna LC1 = 39 N, LC2 = 45 N), natomiast powłoki Cr/(CrN/CrCN)/Cr/DLC wykazują najmniejszą adhezję (LC1 = 27 N, LC2 = 39 N). Z próby Rockwella C wynika, że wszystkie powłoki wykazują dobrą adhezję (HF1-HF2). W tribologicznych próbach zużycia przeprowadzonych metodą kula-tarcza (trzpień-tarcza) powłoki DLC wykazują współczynnik tarcia suchego μ = 0,10÷0,17 w skojarzeniu z Al2O3 a w skojarzeniu z drewnem sosnowym μ = 0,66÷0,68. Wskaźnik zużycia powłok DLC w skojarzeniu z Al2O3 wynosi 3,7×10–7 mm3/Nm, natomiast w skojarzeniu z drewnem sosnowym powłoki nie wykazują mierzalnego zużycia. Próby przemysłowe noży strugarskich ze stali HS6-5-2 pokrytych powłokami Cr/DLC, Cr/CrN/Cr/DLC, Cr/(CrN/CrCN)/Cr/DLC oraz niepokrytych przeprowadzono z wykorzystaniem komercyjnej strugarki dolnowrzecionowej przy obróbce drewna sosnowego. Ponad 2,5-krotnie mniejsze pole zużycia S wykazują noże strugarskie z powłoką Cr/(CrN/CrC)/Cr/DLC w porównaniu z nożami nie pokrytymi. Modyfikacja powierzchni natarcia noży powłokami z warstwą zewnętrzną DLC i podwarstwami na bazie chromu wpływa na zmniejszenie zużycia i pozwala na wydłużenie ich czasu pracy.

EN

The paper presents investigations results of coating properties with DLC (Diamond-Like Carbon) surface layers and three types of sublayers based on chromium: Cr/DLC, Cr/CrN/Cr/DLC and Cr/(CrN/CrCN)/Cr/DLC. It also presents test results of performance durability and wear forms of highspeed steel planer knives with these coatings. Chromium-based sublayers were produced by the cathodic arc evaporation (CVA) and DLC surface layers by the modified cathodic arc evaporation (MCVA). The DLC coatings have a high hardness ca. 34 GPa and good adhesion. In the scratch tests the Cr/DLC coatings exhibit the highest adhesion (critical load LC1 = 39 N, LC2 = 45 N) while coatings Cr/(CrN/CrCN)/Cr/DLC exhibit the lowest adhesion (LC1 = 27 N, LC2 = 39 N). The Rockwell C tests show that all coatings revealed high adhesion (HF1-HF2). DLC coatings in tribological wear tests, conducted by the ball-on-disk (pin-on-disk) method, showed the friction coefficient μ = 0.10÷0.17 in a frictional contact with Al2O3 and μ = 0.66÷0.68 in a frictional contact with pine wood. The wear rate coefficient of DLC coatings in a frictional contact with Al2O3 amounts to 3.7×10–7 mm3/Nm however in a frictional contact with pine wood they do not exhibit any wear. Industrial tests on HS6-5-2 high-speed steel planer knives with Cr/DLC, Cr/CrN/Cr/DLC, Cr/(CrN/CrCN)/Cr/DLC coatings and without any coatings were carried out using a commercial low-spindle planer used for machining pine wood. More than 2.5-fold lower value of wear area S showed planer knives with Cr/(CrN/CrC)/Cr/DLC coatings compared to uncoated planer knives. By modifying the rake faces of planer knives coated with DLC surface layers and chromium-based sublayers it resulted in less wear and allowed for significant improvements in their working time.

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The influence of the MCVA deposition parameters on the structure and tribological properties of DLC coatings on woodworking HSS tool substrates

Pancielejko M., Czyżniewski A., Gilewicz A., Szymański W., Zavaleyev V.

Archives of Materials Science and Engineering

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2013

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Vol. 64, nr 2

160--167

EN

Purpose: The purpose of the present study was the influence of deposition parameters of diamond-like-carbon coatings (DLC), with the modified cathodic vacuum arc (MCVA) method deposited on tool substrates (high-speed steel HS6-5-2) for woodworking, on their structure and tribological properties. Design/methodology/approach: DLC coating was deposited by MCVA method. Structure, adhesion, hardness, internal stresses and friction wear resistance of DLC coatings were tested. Tests of knives coated with DLC and uncoated ones was made by machining medium density fibreboard (MDF) using a industrial milling machine. Findings: The hardness of DLC coatings was 22.7-57.1 GPa. The Raman spectrum of DLC coatings was analysed The high hardness and internal stresses of DLC coating is related to the amount of sp3 bonds. DLC coatings display high adhesion: critical load in the scratch method (LC2 = 22-40 N), from Rockwell test (HF1). The influence of the structure, hardness and adhesion of coatings on wear resistance of coated tools is discussed. Practical implications: The wide range of tribological properties of DLC coatings that are deposited with different parameters may indicate the possibility of their application for tools for wood-like materials in order to increase their durability. Originality/value: Depending of the deposition parameters applied, it is possible to obtain DLC coatings in a wide range of hardness (22.7-57.1 GPa) and adhesion (LC2 = 22-40 N). The industrial tests of cutting wood-based materials indicate that the DLC coatings with different properties improve HSS tool performance. The DLC coatings show antiwear properties required in industry application. The DLC coatings might be apply on high-speed steel planer knives for woodworking industry.

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The cutting properties and wear of the knives with DLC and W-DLC coatings, deposited by PVD methods, applied for wood and wood-based materials machining

Pancielejko M., Czyżniewski A., Gilewicz A., Zavaleyev V., Szymański W.

Archives of Materials Science and Engineering

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2012

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Vol. 58, nr 2

235--244

EN

Purpose: Performance of DLC and W-DLC coated woodworking knives was investigated. The results of testing DLC and W-DLC coating properties as well as the results of life-time tests in the form of wear of HSS and HM knives with these coatings is presents. Design/methodology/approach: DLC coating was deposited by MCVA method, and W-DLC coating was deposited by pulsed RMS. Tests of knives coated with DLC and W-DLC as uncoated ones was made by machining: MDF board, pinewood slats and floorboard - using a typical industrial milling machine. Findings: DLC coating is significantly harder (33-40 GPa) than W-DLC coating (19 GPa). From Rockwell test it can be concluded that both coatings display high adhesion (HF1), whereas in the scratch methods, significantly lower adhesion of DLC coating can be observed (LC2 = 17-21 N) in comparison to W-DLC coating (LC2 = 54 N). Influence of the hardness and adhesion of coatings on wear resistance of coated tools is discussed. Practical implications: Wear resistance of planer knives coated with DLC is by approx. 20%, and W-DLC by approx. 30% higher in comparison with uncoated knives during MDF milling. Wear of planer knives with W-DLC coating is approx. by 10%, and DLC by approx. 25% lower in comparison to uncoated HSS knives during pinewood milling. Lifetime of HM shape tools coated DLC and W-DLC is considerably higher (200-300 %) during floorboard milling. Originality/value: The industrial tests of cutting wood and wood-based materials indicate that the carbon coatings deposited on the tool generally improve its performance and all wear indexes for the tools are lower than for uncoated. The DLC and W-DLC coatings show good antiwear properties required in industry application.

4

Optimization of the deposition parameters of DLC coatings with the MCVA method

Pancielejko M., Czyżniewski A., Zavaleyev V., Pander A., Wojtalik K.

Archives of Materials Science and Engineering

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2012

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Vol. 54, nr 2

60-67

EN

Purpose: The purpose of the present study was to determine the optimal values of selected deposition parameters of diamond-like-carbon coatings (DLC) with the modified cathodic vacuum arc (MCVA) method which ensure obtaining of their most advantageous properties from the perspective of their application for the coating on high-speed steel tool substrates for woodworking. Design/methodology/approach: An analysis was conducted of the investigations into the influence of the selected deposition parameters of DLC coatings on the accepted optimization criteria with the use of the Taguchi module. Adhesion, hardness and friction wear resistance were accepted as the optimization criteria of DLC coatings for high-speed steel substrates. Findings: It was established on the basis of the statistical analysis of the research results that in order to ensure a high adhesion of DLC coatings to high-speed steel substrates, a thick Cr sublayer (0.3 ěm) and a DLC coating (1.8 ěm) is to be used, which is deposited at a high argon pressure (0.25 Pa); no substrate bias (the floating potential) is to be used. In order to obtain high hardness and friction wear resistance, higher values of substrate bias voltages (-80 V) and a low pressure of argon (0.01 Pa) are to be used. Research limitations/implications: To evaluate with more detail the possibility of applying these coatings on tools. I will be kept industrial tests of wearing out tools covered with these DLC coatings. Practical implications: The properties of DLC coatings that are deposited with optimized parameters may indicate the possibility of their application for woodworking or tools for wood-like materials in order to increase their durability. Originality/value: From results of the optimization of selected deposition parameters of DLC on the Taguchi method is possible to appoint coating properties. Depending of the deposition parameters applied, it is possible to obtain DLC coatings in a wide range of hardness (20-60 GPa). The DLC coatings might be apply on high-speed steel knives for woodworking industry.