Process for electrodepositing hard nickel plate

Claim 1

A PROCESS FOR ELECTRODEPOSITING NICKEL PLATE OF HIGH HARDNESS WHICH COMPRISES ESTABLISHING A NICKEL ELECTROPLATING BATH COMPRISING AN AQUEOUS SOLUTION CONTAINING ABOUT 300 GRAMS PER LITER TO ABOUT 375 GRAMS PER LITER OF NICKEL SULFATE, ABOUT 30 GRAMS PER LITER TO ABOUT 60 GRAMS PER LITER OF NICKEL CHLORIDE, ABOUT 30 GRAMS PER LITER TO ABOUT 45 GRAMS PER LITER OF BORIC ACID, ABOUT 0.0018 MOLE TO ABOUT 0.015 MOLE PER LITER OF NICKEL AS AN ADDITION AGENT, SAID NICKEL ADDITION AGENT CONSISTING ESSENTIALLY OF AN AQUEOUS PHOSPHITE SOLUTION HAVING NICKEL AND PHOSPHITE RADICAL IN A RATIO OF ABOUT 1 MOLE OF NICKEL FOR ABOUT 2 TO 2.2 MOLES OF PHOSPHITE RADICAL, AND THE BALANCE ESSENTIALLY WATER, ELECTRODEPOSITING NICKEL THEREFROM AT A CATHODE CURRENT DENSITY OF ABOUT 20 AMPERES PER SQUARE FOOT TO ABOUT 50 AMPERES PER SQUARE FOOT AT A CATHODE DISPOSED IN SAID BATH WHILE MAINTAINING THE PH OF SAID BATH WITHIN A RANGE OF ABOUT PH 1.7 TO PH 3.0, AND WHILE CONTROLLING THE TEMPERATURE OF SAID BATH THROUGHOUT THE FOREGOING OPERATIONS WITHIN A RANGE OF ABOUT 140* F. TO ABOUT 150* F., THEREBY A HARD NICKEL PLATE IS PRODUCED AT THE CATHODE HAVING A HARDNESS AS HIGH AS ABOUT 450 VICKERS.