On The Influence Of Thermal Treating On Properties Of Composite Coatings Deposited By Electroless Process
Maria Trzaska Politechnika Warszawska, Wydział Inżynierii Materiałowej, ul. Wołoska 141, 02-507 Warszawa
Annals 1 No. 1, 2001 pages 106-109
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abstract The aim of the presented paper is focussed on composite coatings with metal deposits and dispersed ceramic phase. The coatings have been deposited by the electroless method. The carried out studies have been reported to composite coatings Ni-P-Si3N4, to their thermal treatments and the analysis of their chemical as well as phase compositions. Studies of hardness and abrasion wear have been also performed. Results of these studies have indicated on the existence of 7.8% in weight of phosphorus in the deposited coatings. The microstructures of the surface and within the cross-section of the obtained coatings Ni-P-Si3N4 are shown in Fig. 1. The phase composition of the coatings Ni-P-Si3N4 is presented in Fig. 2. The phase composition of the coatings after their thermal treatments at the temperature 673 K is shown in Fig. 3. Results of the measuring of the microhardness of the substrate (steel St3) and the coatings Ni, Ni-P, Ni-P-Si3N4 before thermal treatments as well as of the coatings Ni- P, Ni-P-Si3N4 after thermal treatments are presented in Table 1, respectively. Figure 4 shows the results of studies of the abrasive wear of the coatings Ni, Ni-P, Ni-P-Si3N4 and of the coatings Ni-P, Ni-P-Si3N4 after the thermal treatments, respectively. The performed studies have proved that the presence of phosphorus and of the ceramic dispersive phase as well as the thermal treatments importantly influenced the useful properties of the coatings manufactured by the electroless process.