Adhesivity testing of the hard PACVD coatings applied on hot work tool steel

U radu su analizirana svojstva prionjivosti tvrdih PACVD prevlaka na alatnom čeliku za topli rad, X38CrMoV5-3. Provedena su ispitivanja debljine i prionjivosti višeslojnih prevlaka TiN/TiCN i TiN/TiBN na sobnoj temperaturi i nakon kratkotrajnog izlaganja povišenoj temperaturi od 500°C. Debljina prevlaka određena je kalotestom a prionjivost prevlaka je određena Rockwell-ovom metodom utiskivanja indentora prema normi VDI 3198 i „load scanning“ ispitivanjem. Iz provednih ispitivanja zaključeno je da na sobnoj temperaturi ujednačenu otpornost na adhezijsko trošenje imaju neprevučeni uzorak, plazmatski nitriran uzorak i uzorak prevučen PACVD prevlakom TiN/TiCN, dok je uzorak prevučen PACVD prevlakom TiN/TiBN pokazao oko 35% lošiju otpornost. Pri povišenoj temperaturi plazmatski nitriran uzorak je pokazao najbolju otpornost na adhezijsko trošenje, a uzorak prevučen PACVD prevlakom TiN/TiCN se pokazao samo 3% lošiji, za razliku od neprevučenog uzorka i prevučenog PACVD prevlakom TiN/TiBN koji su se pokazali lošiji 20 odnosno 27%. Na osnovi rezultata ispitivanja tvrdih PACVD prevlaka predlaže se TiN/TiCN prevlaka za izradu kalupa za tlačni lijev aluminijskih legura.This thesis analyzes the adhesion properties of PACVD hard coatings on hot-work tool steel, X38CrMoV5-3. Studies of thickness and adhesion of multi-layered coatings, TiN/TiCN and TiN/TiBN, have been conducted at room temperature and after short-term exposure to elevated temperature of 500°C. The thickness of the coating is determined by a calotest, the adhesion of coatings is determined by Rockwell indenter penetration, according to the VDI 3198 norm, and by "load scanning" testing. From the conducted tests it was concluded that the uncoated sample, the plasma nitrided sample and the sample coated with the PACVD TiN/TiCN coating have a uniform resistance to adhesion wear, while the sample coated with the PACVD TiN/TiBN coating showed about 35% poorer resistance. At elevated temperature plasma nitrided sample showed the best resistance to wear, and the sample coated with the PACVD TiN/TiCN coating proved only 3% worse, unlike the uncoated sample and the sample coated with the PACVD TiN/TiBN coating which proved 20 and 27% worse. For the purpose of making molds, used for casting of aluminum alloys, the application of TiN/TiCN coatings is proposed based on the test results obtained by testing PACVD hard coatings