The Paton Welding Journal, 2015, №02



2015 №02 (03)

DOI of Article 10.15407/tpwj2015.02.04

2015 №02 (05)

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The Paton Welding Journal, 2015, #2, 19-25 pages  

UPERSONIC PLASMA GAS AIR SPRAYING OF CERMET COATINGS OF THE (Ti, Cr)C-NiCr SYSTEM

Yu.S. Borisov, A.L. Borisova, M.V. Kolomytsev And O.P. Masyuchok

E.O. Paton Electric Welding Institute, NASU. 11 Bozhenko Str., 03680, Kiev, Ukraine. E-mail: office@paton.kiev.ua
 
 
Abstract
Effect of plasma gas air spraying (PGAS) factors (plasmatron power, consumption of plasma gas, spraying distance, anode diameter) of mechanical mixture from double titanium-chromium carbide and nichrome powders on characteristics of produced coatings (structure, microhardness, porosity, chipping resistance) was investigated. Program of experiments was composed using mathematical planning method. Regression equations, determining quantitative dependence of values of average and maximum microhardness, stability of microhardness indices and level of chipping on spraying process factors, were received based on data processing results. Indices of heat content in plasma jet and duration of powder particle passing through plasma jet were used for analysis of the results. It is determined that mode of plasma jet outflow and value of its heat content have the largest effect on structure and properties of produced coatings. Using 10 mm diameter anode, providing supersonic jet outflow mode at 5.6 kWрh/m³ heat content index, for PGAS of coatings from mechanical mixture of titanium-chromium carbide and nichrome powders (3:1) promotes for formation of dense coatings (porosity <1 %) with cermet structure (titanium-chromium carbide and nichrome). Such coatings have average microhardness 12.6 GPa that 1.5 times exceeds microhardness of thermal coatings from mechanical mixture of chromium carbide and nichrome powders (8.6 GPa). 20 Ref., 6 Tables, 2 Figures.
 
 
Keywords: cermets, double titanium-chromium carbide, supersonic plasma gas air spraying, coating properties, microhardness, experiment planning
 
 
Received:                21.11.14
Published:               01.04.15
 
 
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