Patent ID: 6095107
Filing Date: 2000-08-01
Classification: C23C,F16C,Y10T

Abstract:
A reciprocating piston engine comprising a crankcase made of an aluminum alloy having cylinder linings made from a steel-molybdenum coating applied by thermal spraying, wherein the steel-molybdenum coating forming the cylinder linings is applied by spraying a mixture of 10-70% molybdenum and 90-30% steel onto the aluminum alloy, and wherein the steel satisfies at least one requirement from the group consisting of; a hardness after thermal spraying from about 300 to 500 HV 0.3; an annealed hardness before thermal spraying from about 300 to about 450 HV 0.3; a hardness chosen so that a thermally sprayed mixture of 30 wt. % molybdenum and 70 wt. % of the steel has a hardness from about 550 to about 850 HV 0.05; a hardness chosen so that a thermally sprayed mixture of 50 wt. % molybdenum and 50 wt. % of the steel has a hardness from about 550 to about 850 HV 0.05; a hardness chosen so that thermally sprayed mixtures in the range from about 30 wt. % molybdenum/70 wt. % of the steel to about 50 wt. % molybdenum/50 wt. % of the steel have a hardness difference selected from the group consisting of (i) at most 100 HV 0.05; (ii) at most a 10% higher hardness HV 0.05 than the softest mixture in that range; and (iii) a hardness HV 0.05 deviating by at most .+-.10% compared to the mixture of 30 wt. % molybdenum/70 wt. % of the steel; and the coating satisfies at least one requirement selected from the group consisting of: C content 0.7-2.1 wt. % of the steel; Cr content 1.0 to 15 wt. % of the steel; Si content 0.5-2 wt. % of the steel; Mo content 2.5-50 wt. % of the steel; W content 2.5-30 wt. % of the steel; Mo + W content 2.5-50 wt. % of the steel;  .alpha.-Fe matrix at least 50 wt. % of Fe;fine Cr, Mo, W and/or MN carbides not over 1 micron in size in an .alpha.-Fe matrix;a thickness from about 80 to 350 microns;applied to a surface of the body roughened by a stream of particles and/or fluid;applied to a surface treated to a mean rugosity (Ra) from about 4 to 35 microns;having a porosity not over 10 vol. %;having predominately isolated pores; andhaving a majority of the pores in a size range from about 2 to about 40 microns.