Abstract Contact fatigue failure is one of the failure type for steel gear．This paper researched the contact fatigue strength of Ni-P-Co alloy coating on surface of gears made from 45# stee1．Several studies on the alloying coating，such as surface shape，surface roughness，micro-hardness and shape characteristic of fatigue pitting hole were carried out． The experimental results were analyzed and conclusion was as follows：contact fatigue life and strength of steel gears with Ni-P-Co alloy coating and air-cooling after heat-treatm ent with temperature of 450C are increased remarkably．
LI Xiao-Zhou, HUANG Hua-Liang. Research on contact-fatigue strength of 45 # steel gear drives with Ni-P-Co alloy coating. Chinese Journal of Engineering Design, 2002, 9(4): 211-214.
