| Spray-forming Al-Si alloys spray deposited composite material with its high specific strength and specific modulus, low coefficient of expansion, low density, good dimensional stability, thermal conductivity, excellent performance aluminum, wear parts for automotive applications, and in line with car development trends in sustainable timber industry, the paper further increase the surface hardness and wear resistance, carried out surface preparation and study of wear resistant coati ngs to expand its application in the automotive industry.In this paper, detonation spraying and HVOF spray deposition method Si Cp reinforced aluminum alloy surface prepared by various WC-Co coatings. Scanning electron microscopy(EDAX), X-ray apparatus for coating phase structure and microstructure were studied; the use of gray values for the porosity of the coating were tested; Rally test using bonding strength; with significant micro-Vickers hardness test of the coating hardness and toughness cracking; f inal testing abrasive wear resistance of the coating on the MLS-225 wet sand grain wear tester; to explore the exploding fuel ratio of oxygen spray, HVOF spraying spraying distance, spraying material WC-Co in Co content on the coating properties. Studies h ave shown that:With detonation spraying fuel ratio of oxygen increases, the degree of coating is decomposed into W2 C and WC decarburization W gradually increases in oxy-fuel ratio of the highest degree of decomposition, the decomposition will result in a reduction of the WC particles and the coating adhesion when 1.8 Co phase loss. The hardness of the coating with increased oxygen fuel ratio increased and then decreased after presentation, when oxy-fuel ratio of 1.5 when the coating hardness and wear resistance to achieve the best combination; with increasing distance HVOF spray coating hardness and wear resistance increases with increasing distance of the spray, the best spraying distance is 380 mm, further increasing the spraying distance will affect the WC-Co particle kinetic energy and decay; prepared deflagration in Si Cp / Al-Si composite surface sprayed WC-Co coatings and HVOF WC-Co coatings allow its wear resistance is increased 1.51 to 3.58 times, and knocking sprayed WC-Co coatings compared HVOF WC-Co coatings overall performance and wear resistance.In the deflagration spraying process, with different degrees of decarbonization coating, abrasive wear resistance of the coating vary. At higher levels of the coating decarbonization, WC decarbonization d ecomposed into W2 C and W, reduce the number of WC particles coating, the lack of anti-wear coating WC particles, abrasive coating only WC will soon wear off thus wear substrate; slight decarburization coatings, WC particles at more than the other oxy-fuel ratio of the deposited coating prepared isoform process, coupled with uniform distribution of Co binder phase in the coating, the wear mechanism the Co binder phase is gradually worn, further consolidation led to the loss of WC particles and fatigue, damag e, peeling, so wear performance than decarbonization due to severe lack of good coating WC particles.Spray deposited Si C partical reinforced detonation spraying aluminum matrix composites optimum parameters are as follows: oxygen flow 1.5m3/h, acetylene flow 1.0m3/h, the powder feeding gas flow rate 0.6 m3/h, burst frequency 4 times/sec, spraying distance 165 mm, oxy-fuel ratio of 1.5.Performance of coatings were: hardness HV0.5 = 1088, aporosity of 1.72%, the bonding strength of 43.01 M Pa, crack toughness 1.81MPam(1/2). |
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