Stress controlled electroless nickel deposits

Claim 1

A METHOD OF PRODUCING A NICKEL-PHOSPHORUS ALLOY COATING HAVING A PREDETERMINED AND CONTROLLED RESIDUAL STRESS IN THE RANGE OF FROM ABOUT +15 KSI TENSILE STRESS TO ABOUT -17 KSI COMPRESSIVE STRESS THEREIN AND CHEMICALLY DEPOSITED ON A METAL SUBSTRATE SELECTED FROM THE GROUP CONSISTING OF BERYLLIUM, ALUMINUM, TITANIUM, IRON, NICKEL, COPPER AND THEIR ALLOYS, SAID METHOD COMPRISING INTRODUCING THE METAL SUBSTRATE INTO AN AQUEOUS BATH OF THE NICKEL CATION-HYPOPHOSPHITE ANION TYPE, THE BATH HAVING A HYPOPHOSPHITE ION CONCENTRATION EXPRESSED IN MOLES PER LITER OF FROM ABOUT 0.1 TO ABOUT 0.5, MAINTAINING THE PH OF THE BATH AT A PREDETERMINED VALUE IN THE RANGE FROM ABOUT 3.5 TO ABOUT 7 AND THE TEMPERATURE OF THE BATH AT A PREDETERMINED VALUE IN THE RANGE FROM ABOUT 70*C. TO ABOUT 95*C. TO DEPOSIT ON THE METAL SUBSTRATE A NICKELPHOSPHORUS COATING HAVING A PHOSPHORUS CONTENT OF A PREDETERMINED VALUE IN THE RANGE BETWEEN ABOUT 13 PERCENT AND ABOUT 3 PERCENT, MAINTENANCE OF THE PH OF THE BATH OF THE UPPER END OF THE PH RANGE COUPLED WITH MAINTENANCE OF THE TEMPERATURE OF THE BATH AT THE LOWER END OF THE TEMPERATURE RANGE PRODUCING A COATING HAVING A PHOSPHORUS CONTENT AT THE LOWER END OF THE PHOSPHORUS RANGE AND MAINTENANCE OF THE PH OF THE BATH AT THE LOWER END OF THE PH RANGE COUPLED WITH MAINTENANCE OF THE TEMPERATURE OF THE BATH NEAR THE UPPER END OF THE TEMPERATURE RANGE PRODUCING A COATING HAVING A PHOSPHORUS CONTENT AT THE UPPER END OF THE PHOSPHORUS RANGE, A COATING HAVING A PHOSPHORUS CONTENT NEAR THE LOWER END OF

Claim 2

A METHOD OF PRODUCING A NICKEL-PHOSPHORUS ALLOY COATING HAVING A PREDETERMINED AND CONTROLLED RESIDUAL STRESS IN THE RANGE OF FROM ABOUT +15 KSI TENSILE STRESS TO ABOUT -17 KSI COMPRESSIVE STRESS THEREIN AND CHEMICALLY DEPOSITED ON A METAL SUBSTRATE SELECTED FROM THE GROUP CONSISTING OF BERYLLIUM, ALUMINUM, TITANIUM, IRON, NICKEL, COPPER AND THEIR ALLOYS, SAID METHOD COMPRISING INTRODUCING THE METAL SUBSTRATE INTO AN AQUEOUS BATH OF THE NICKEL CATION-HYPOPHOSPHITE ANION TYPE, THE BATH HAVING A HYPOPHOSPHITE ION CONCENTRATION EXPRESSED IN MOLES PER LITER OF FROM ABOUT 0.1 TO ABOUT 0.5, MAINTAINING THE PH OF THE BATH AT A PREDETERMINED VALUE IN THE RANGE FROM ABOUT 3.5 TO ABOUT 7 AND THE TEMPERATURE OF THE BATH AT A PREDETERMINED VALUE IN THE RANGE FROM ABOUT 70*C. TO ABOUT 95*C. TO DEPOSIT ON THE METAL SUBSTRATE A NICKELPHOSPHORUS COATING HAVING A PHOSPHORUS CONTENT OF A PREDETERMINED VALUE IN THE RANGE BETWEEN ABOUT 13 PERCENT AND ABOUT 3 PERCENT, MAINTENANCE OF THE PH OF THE BATH OF THE UPPER END OF THE PH RANGE COUPLED WITH MAINTENANCE OF THE TEMPERATURE OF THE BATH AT THE LOWER END OF THE TEMPERATURE RANGE PRODUCING A COATING HAVING A PHOSPHORUS CONTENT AT THE LOWER END OF THE PHOSPHORUS RANGE AND MAINTENANCE OF THE PH OF THE BATH AT THE LOWER END OF THE PH RANGE COUPLED WITH MAINTENANCE OF THE TEMPERATURE OF THE BATH NEAR THE UPPER END OF THE TEMPERATURE RANGE PRODUCING A COATING HAVING A PHOSPHORUS CONTENT AT THE UPPER END OF THE PHOSPHORUS RANGE, A COATING HAVING A PHOSPHORUS CONTENT NEAR THE LOWER END OF

Claim 3

A method of producing a nickel-phosphorus alloy coating having a predetermined and controlled residual stress in the range of from about +15 ksi tensile stress to about -17 ksi compressive stress therein and chemically deposited on a metal substrate selected from the group consisting of beryllium, aluminum, titanium, iron, nickel, copper and their alloys, said method comprising introducing the metal substrate into an aqueous bath of the nickel cation-hypophosphite anion type, the bath having a hypophosphite ion concentration expressed in moles per liter of from about 0.1 to about 0.5, maintaining the pH of the bath at a predetermined value in the range from about 3.5 to about 7 and the temperature of the bath at a predetermined value in the range from about 70*C. to about 95*C. to deposit on the metal substrate a nickel-phosphorus coating having a phosphorus content of a predetermined value in the range of between about 13 percent and about 3 percent, maintenance of the pH of the bath at the upper end of the pH range coupled with maintenance of the temperature of the bath at the lower end of the temperature range producing a coating having a phosphorus content at the lower end of the phosphorus range and maintenance of the pH of the bath at the lower end of the pH range coupled with maintenance of the temperature of the bath near the upper end of the temperature range prOducing a coating having a phosphorus content at the upper end of the phosphorus range, a coating having a phosphorus content near the lower end of the phosphorus range tending to be in tensile stress and a coating having a phosphorus content near the upper end of the phosphorus range tending to be in compressive stress, contacting the metal substrate with the bath for a time period sufficient to deposit on the metal substrate a coating having a predetermined thickness of at least about one-tenth mil, removing the coated metal substrate from the bath and cooling the coated metal substrate to ambient temperatures, whereby to produce a metal substrate having chemically deposited thereon a nickel-phosphorus coating having a predetermined and controlled residual stress therein.

Claim 4

A method of producing a nickel-phosphorus alloy coating having a predetermined and controlled residual stress in the range of from about +15 ksi tensile stress to about -17 ksi compressive stress therein and chemically deposited on a metal substrate selected from the group consisting of beryllium, aluminum, titanium, iron, nickel, copper and their alloys, said method comprising introducing the metal substrate into an aqueous bath of the nickel cation-hypophosphite anion type, the bath having a hypophosphite ion concentration expressed in moles per liter of from about 0.1 to about 0.5, maintaining the pH of the bath at a predetermined value in the range from about 3.5 to about 7 and the temperature of the bath at a predetermined value in the range from about 70*C. to about 95*C. to deposit on the metal substrate a nickel-phosphorus coating having a phosphorus content of a predetermined value in the range of between about 13 percent and about 3 percent, maintenance of the pH of the bath at the upper end of the pH range coupled with maintenance of the temperature of the bath at the lower end of the temperature range producing a coating having a phosphorus content at the lower end of the phosphorus range and maintenance of the pH of the bath at the lower end of the pH range coupled with maintenance of the temperature of the bath near the upper end of the temperature range prOducing a coating having a phosphorus content at the upper end of the phosphorus range, a coating having a phosphorus content near the lower end of the phosphorus range tending to be in tensile stress and a coating having a phosphorus content near the upper end of the phosphorus range tending to be in compressive stress, contacting the metal substrate with the bath for a time period sufficient to deposit on the metal substrate a coating having a predetermined thickness of at least about one-tenth mil, removing the coated metal substrate from the bath and cooling the coated metal substrate to ambient temperatures, whereby to produce a metal substrate having chemically deposited thereon a nickel-phosphorus coating having a predetermined and controlled residual stress therein.

Claim 5

A method of producing an annealed coating having a predetermined and controlled residual stress in the range of from about +19 ksi tensile stress to about -21 ksi compressive stress therein deposited on a metal substrate selected from the group consisting of beryllium, aluminum, titanium, iron, nickel, copper and their alloys, said method comprising introducing the metal substrate into an aqueous bath of the nickel cation-hypophosphite anion type, the bath having a hypophosphite ion concentration expressed in moles per liter of from about 0.1 to about 0.5, maintaining the pH of the bath at a predetermined value in the range from about 3.5 to about 7 and the temperature of the bath at a predetermined value in the range from about 70*C. to about 95*C. to deposit on the metal substrate a nickel-phosphorus coating having a phosphorus content of a predetermined value in the range of between about 13 percent and about 3 percent, maintenance of the pH of the bath at the upper end of the pH range coupled with maintenance of the temperature of the bath at the lower end of the temperature range producing a coating having a phosphorus content at the lower end of the phosphorus range and maintenance of the pH of the bath at the lower end of the pH range coupled with maintenance of the temperature of the bath near the upper end of the temperature range producing a coating having a phosphorus content at the upper end of the phosphorus range, a coating having a phosphorus content near the lower end of the phosphorus range tending to be in tensile stress and a coating having a phosphorus content near the upper end of the phosphorus range tending to be in compressive stress, contacting the metal substrate with the bath for a time period sufficient to deposit on the metal substrate a coating having a predetermined thickness of at least about one-tenth mil, whereby to produce a metal substrate having chemically deposited thereon a nickel-phosphorus coating having a controlled stress therein, heating the coated metal substrate to a temperature in the range from about 250*F. to about 600*F. for a time period of at least about one hour, and cooling the coated metal substrate to ambient temperatures, whereby to produce a metal substrate having thereon a coating having a predetermined and controlled residual stress therein.

Claim 6

A method of producing an annealed coating having a predetermined and controlled residual stress in the range of from about +19 ksi tensile stress to about -21 ksi compressive stress therein deposited on a metal substrate selected from the group consisting of beryllium, aluminum, titanium, iron, nickel, copper and their alloys, said method comprising introducing the metal substrate into an aqueous bath of the nickel cation-hypophosphite anion type, the bath having a hypophosphite ion concentration expressed in moles per liter of from about 0.1 to about 0.5, maintaining the pH of the bath at a predetermined value in the range from about 3.5 to about 7 and the temperature of the bath at a predetermined value in the range from about 70*C. to about 95*C. to deposit on the metal substrate a nickel-phosphorus coating having a phosphorus content of a predetermined value in the range of between about 13 percent and about 3 percent, maintenance of the pH of the bath at the upper end of the pH range coupled with maintenance of the temperature of the bath at the lower end of the temperature range producing a coating having a phosphorus content at the lower end of the phosphorus range and maintenance of the pH of the bath at the lower end of the pH range coupled with maintenance of the temperature of the bath near the upper end of the temperature range producing a coating having a phosphorus content at the upper end of the phosphorus range, a coating having a phosphorus content near the lower end of the phosphorus range tending to be in tensile stress and a coating having a phosphorus content near the upper end of the phosphorus range tending to be in compressive stress, contacting the metal substrate with the bath for a time period sufficient to deposit on the metal substrate a coating having a predetermined thickness of at least about one-tenth mil, whereby to produce a metal substrate having chemically deposited thereon a nickel-phosphorus coating having a controlled stress therein, heating the coated metal substrate to a temperature in the range from about 250*F. to about 600*F. for a time period of at least about one hour, and cooling the coated metal substrate to ambient temperatures, whereby to produce a metal substrate having thereon a coating having a predetermined and controlled residual stress therein.