تأثير پيش عمليات نيتروژن دهي پلاسمايي فولاد گرمكار H11 AISI بر رفتار سايشي پوشش TiN ايجاد شده به روش PACVD

Effect of pre-plasma nitriding of hot work steel on wear properties of TiN coating deposited using PACVD

The aim of this study was to investigate the effect of pre-treatment plasma nitriding (PN) on mechanical and tribological behavior of TiN coatings produced by plasma assisted chemical vapor deposition (PACVD). The heat treatment of quench and temper carried out on hot work AISI Hll (DIN 1.2343) steel samples. A group of samples were plasma nitrided at 500 gC for 4 h in an atmosphere containing 25vol% nitrogen and 75vol% hydrogen. Then TiN layer was deposited on all of samples at 520 QC temperature, 8 kHz frequency and 33% duty cycle. The microstructural, mechanical and tribological properties of the coatings were investigated using SEM, WDS, microhardness tester and pin-on-disc wear test. The load of wear test was ION and the samples were worn against different pins, ball-bearing steel (DIN 1.3505) and cemented tungsten carbide (WC-Co). The results indicate that the difference of hardness between the samples with PN-TiN layer and those samples with only TiN layer without PN was 450 HV and the former samples showed a significant amount of wear resistance in comparison to the latter ones.