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Abstract :
[en] Chemical nickel deposits, which contain boron or phosphorus, are used to improve the wear resistance of various substrates for many years. So, resistance to wear and the properties of the different deposits was the subject of many studies.
Standard samples for Taber abrasion test (10 ** 10 cm, 3 mm thick) was coated with various compositions of chemical nickel: 3 types of nickel-phosphorus and 2 types of nickel-boron stabilized with either thallium (nickel-boron-thallium) or lead (nickel-boron (Pb)).
Some deposits were subjected to heat treatment to optimize the hardness of deposits.
The hardness of nickel-boron deposits (Pb) exceeds 1100 hk50 after heat treatment. This value is significantly higher than those obtained on other deposits. Indeed, other values are in the range 900-1100 hk50, whether nickel-phosphorus or nickel-boron-thallium.
Abrasion wear resistance of all deposits is studied by Taber test with abrasive CS-10 wheels.
Resistance to wear by abrasion of all samples is enhanced by heat treatment. The least successful candidates (medium phosphorus and nickel-boron-thallium) present the best evolution after thermal treatment.
Low and high phosphorus deposits have similar Taber Wear Index: 10-12 after heat treatment.
Once again, the deposit which has the best performance is nickel-boron (Pb), with a Taber index of 6 after heat treatment.
Scratch tests were also conducted on the samples to ascertain the adhesion of the coatings and identify the damage mechanisms.
Morphological, structural and chemical analyses conducted on various samples have confirmed these results and indicate that nickel-boron (Pb) is indeed the best candidates for resistance to abrasive wear.
