DETERMINATION of COATING PARAMETERS in ELECTROLESS Ni-P COATINGS AND THEIR EFFECTS on MECHANICAL PROPERTIES


Thesis Type: Doctorate

Institution Of The Thesis: Gazi University, Fen Bilimleri Enstitüsü, Turkey

Approval Date: 2010

Thesis Language: Turkish

Student: Ulaş MATİK

Supervisor: RAMAZAN ÇITAK

Abstract:

Electroless Nickel (EN) plating is a coating technique of nickel ions on substrate by autocatalytic or chemical reduction. EN plating were applied on lots of industry possess because of their excellent wear and corrosion resistance, solderability and providing uniform coating thickness notwithstanding part shape. In Ni-P alloys, phosphor content has strong affect on properties especially on coating structure. Ni-P alloys are separated three groups; low, medium and high phosphor according with phosphor content. In this study, the effect of heat treatment on hardness and wear characteristics of Ni-P coatings was investigated. For this aim, low, medium and high phosphor coatings have been applied on AISI 1010, AISI 1020 and AISI 304 samples using three different solutions to apply different tests and analysis. Isothermal heat treatments were applied on some of the coated specimens at varying temperature under flowing Ar atmosphere. DSC, SEM, EDS, XRD, surface roughness, optical microscope analysis and microhardness and wear tests have carried out. It has been found that the highest hardness was provided at 400 °C and hardness was decreased at higher temperatures. It has been determined that as wear amount was decreasing up to 300 oC higher temperature has no effect on wear properties. It has also been found that friction forces were decreased with increasing phosphor content.