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SEM and EDS Characterization of Porous Coatings Obtained On Titaniumby Plasma Electrolytic Oxidation in Electrolyte Containing Concentrated Phosphoric Acid with Zinc Nitrate

Rokosz K., Hryniewicz T., Pietrzak K., Malorny W.

Advances in Materials Science

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2017

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Vol. 17, nr 2(52)

41--54

EN

The SEM and EDS results of porous coatings formed on pure titanium by Plasma Electrolytic Oxidation (Micro Arc Oxidation) under DC regime of voltage in the electrolytes containing of 500 g zinc nitrate Zn(NO3)2·6H2O in 1000 mL of concentrated phosphoric acid H3PO4 at three voltages, i.e. 450 V, 550 V, 650 V for 3 minutes, are presented. The PEO coatings with pores, which have different shapes and the diameters, consist mainly of phosphorus, titanium and zinc. The maximum of zinc-to-phosphorus (Zn/P) ratio was found for treatment at 650 V and it equals 0.43 (wt%) | 0.20 (at%), while the minimum of that coefficient was recorded for the voltage of 450 V and equaling 0.26 (wt%) | 0.12 (at%). Performed studies have shown a possible way to form the porous coatings enriched with zinc by Plasma Electrolytic Oxidation in electrolyte containing concentrated phosphoric acid H3PO4 with zinc nitrate Zn(NO3)2·6H2O.

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Fabrication and characterisation of porous, calcium enriched coatings on titanium after plasma electrolytic oxidation under DC regime

Rokosz K., Hryniewicz T., Pietrzak K., Sadlak P., Valíček J.

Advances in Materials Science

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2017

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Vol. 17, nr 4(54)

55--67

EN

The purpose of this work is to produce and characterize (chemical composition and roughness parameters) porous coatings enriched in calcium and phosphorus on the titanium (CP Titanium Grade 2) by plasma electrolytic oxidation. As an electrolyte, a mixture of phosphoric acid H3PO4 and calcium nitrate Ca(NO3)2·4H2O was used. Based on obtained EDS and roughness results of PEO coatings, the effect of PEO voltages on the chemical composition and surface roughness of porous coatings was determined. With voltage increasing from 450 V to 650 V, the calcium in PEO coatings obtained in freshly prepared electrolyte was also found to increase. In addition, the Ca/P ratio increased linearly with voltage increasing according to the formula Ca/P = 0.035·U+0.176 (by wt%) and Ca/P = 0.03·U+0.13 (by at%). It was also noticed that the surface roughness increases with the voltage increasing, what is related to the change in coating porosity, i.e. the higher is the surface roughness, the bigger are pores sizes obtained.

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Energy saving using heat exchangers covered with porous coatings

Wójcik T. M.

Structure and Environment

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2010

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Vol. 2. no. 3

35-39

EN

Exploitation of technical devices is always related to the energy consumption. Thus, if more efficient heat exchangers are used as part of mechanical systems, it is possible to save energy. The paper presents possible ways of producing more efficient heat transfer surfaces working under the nucleate boiling mode. When porous coverings are used, significant reduction of temperature differences is noticed at the same heat flux. It leads to higher energy efficiency.

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Experimental Investigations on the Structural-Osteoinductive Properties of Porous Coatings on Orthopaedic Implants

Uklejewski R., Winiecki M., Mielniczuk J., Auguściński A., Rogala P.

Machine Dynamics Problems

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2006

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Vol. 30, No. 4

171-180

EN

The adaptive bone tissue ingrowth into the pore space of a porous coating on orthopaedic implants is influenced by the structural-osteoinductive properties of this coating. The effective bone tissue ingrowth determines the proper fixation of the porous implant in its bony surroundings. The adequate evaluation of the structural-adaptive compatibility of bone-implant interface can be performed on the basis of the two-phase poroelastic biomechanical model of bone tissue and of implant porous coatings with the set of original parameters characterizing the poroaccessibility of implant porous coatings: the effective volumetric porosity φVef, the index of the porous coating space capacity VPM, the effective pore depth ρdef, the representative surface porosity φSrep, the representative pore size ρSrep, the representative angle of the poroaccessibility Ωrep, the index of the enlargement of the adhesive surface of bone-implant interface Ψ, which is proposed in (Mielniczuk et al., 2006; Winiecki et al., 2006; Uklejewski et al., 2005a and 2005b; Winiecki, 2006) to the biostructural evaluation of the porous coated orthopedic implants. This paper presents the results of experimental investigations of the microgeometrical properties of implants porous coatings made with contact profile measurement on the representative examples of endoprostheses stems.