Weldphos Mn is formulated for conversion of iron and steel to a non-metallic, polycrystalline coating containing heavy manganese phosphate by tank immersion application. The excellent wear-resistant and oil-retentive properties for lubricity and corrosion resistance is ideal to prevent metal to metal contact between moving parts in engine blocks; gears, pistons, rings, cylinder liners, camshafts, transmission gears, and other internal engine components. The coating weights range from 1500 to 5000 mg/ft2 on machined surfaces to provide rapid break-in of abrasive surfaces, preventing galling and scoring.
The applied dark, matte-grey phosphate coating acts as a sacrificial surface that is slowly attrited with time, leaving an oil-trapping, dimpled surface that improves lubricity of the resultant abrasive surface. When the phosphate coating imparted by Weldphos Mn is impregnated with a rust-proof oil such as Guardcoat™ Oil, the sealed coating typically provides protection for the life of the product.
Weldphos Mn operates similar to a typical manganese phosphate bath, which is charged at 10% by volume, operates between 82oC to 99oC (180oF to 210oF), with immersion for 10 to 30 minutes and total acid/free acid ratio of 5:1 to 6:1. The balance of the bath (total acid) when compared to the bath activity (free acid) is critical to control crystal size and coating uniformity. A ratio of 5:1(5:5 to 6:1) to 6:1 is recommended and maintainted with additions of managanese carbonate. High iron content in the bath can be lowered by hydrogen peroxide treatment.
