Process for electrodepositing titanium diboride from fused salts

Claim 2

A PROCESS FOR PRODUCING SUBSTANTIALLY PURE COHERENT TITANIUM DIBORIDE ON A CATHODE BY ELECTRODEPOSITION COMPRISING: PROVIDING A FUSED SALT BATH CONSISTING ESSENTIALLY OF AT LEAST ONE ALKALI METAL FLUORIDE SELECTED FROM THE GROUP CONSISTING OF THE FLUORIDES OF LITHIUM, SODIUM, POTASIUM, RUBIDIUM AND CESIUM; HEATING SAID BATH TO A TEMPERATURE OF ABOUT 1,000* TO 1,400*F IN A NONCONTAMINATING ATMOSPHERE; ESTABLISHING IN THE BATH A FLUBORATE ION CONCENTRATION OF APPROXIMATELY 1-20 PERCENT, BY WEIGHT, AND A TITANIUM ION CONCENTRATION APPROXIMATELY 0.5-4 PERCENT, BY WEIGHT; AND ESTABLISHING A CURRENT DENSITY AT THE CATHODE OF APPROXIMATELY 9-500 MA/CM2, SAID CURRENT DENSITY BEING APPROXIMATELY 9-35 MA/CM2 AT A TEMPERATURE OF 1000*-1,100*F, 25-100 MA CM2 AT A TEMPERATURE OF 1,100*-1,250*F AND 40-500 MA/CM2 AT A TEMPERATURE OF 1,250*-1,200*F.

Claim 3

The process of claim 1 wherein said fluoborate concentration is 2-5 percent, said titanium ion concentration is 1-2 percent and said current density is 50-300 ma/cm2.

Claim 4

The process of claim 2 wherein said fused salt bath comprises a mixture of 40 to 60 mol percent potassium fluoride and 60 to 40 mol percent lithium fluoride.

Claim 5

The process of claim 3 wherein said fluoborate ion concentration is established by dissolving boron trifluoride gas into the fluoride mixture.

Claim 6

The process of claim 2 wherein said fused salt bath comprises a eutectic mixture or near eutectic mixture of the fluorides of potassium, lithium and sodium.

Claim 7

The process of claim 5 wherein said fluoborate concentration is established by dissolving boron trifluoride gas into the fluoride mixture.

Claim 8

The process of claim 1 wherein said fused salt bath additionally contains at least one fluoride selected from the group consisting of the fluorides of magnesium, barium, calcium, strontium and other metals having a reduction potential more negative than that required for titanium diboride deposition.

Claim 9

The invention of claim 7 wherein said current density is established by imposing a potential between said cathode and an anode consisting essentially of titanium and boron.

Claim 10

The process of claim 7 including the step of, prior to establishing said current density, purifying the fused salt bath until the residual oxianion contamination level therein is no greater than that amount which will produce a current maximum of 10 ma/cm2 aT an anodic potential of 1.5 volts impressed on a carbon electrode therein.

Claim 11

The process of claim 1 including the step of, prior to establishing said current density, purifying the fused salt bath until the residual oxianion contamination level therein is no greater than that amount which will produce a current maximum of 10 ma/cm2 at an anodic potential of 1.5 volts impressed on a carbon electrode therein.

Claim 12

A process for producing substantially pure coherent titanium diboride on a cathode by electrodeposition comprising: providing a fused salt bath consisting essentially of a eutectic or near eutectic mixture of the fluorides of potassium, lithium and sodium; heating the bath to a temperature of about 1,000* to 1,400*F in a noncontaminating atmosphere; establishing in the bath a fluoborate ion concentration of approximately 2 to 5 percent, by weight and a titanium ion concentration of approximately 1-2 percent, by weight; purifying the bath by nonanodically introducing therein fine chips of elemental boron to react with contaminants therein; and establishing a current density at the cathode of 9-500 milliamperes per square centimeter, said current density being approximately 9-35 ma/cm2 at a temperature of 1,000*-1,100*F, 25-100 ma/cm2 at a temperature of 1,100*-1,250*F and 40-500 ma/cm2 at a temperature of 1,250*-1,400*F.

Claim 13

A process for producing substantially pure coherent titanium diboride on a cathode by electrodeposition comprising: providing a fused salt bath consisting essentially of a eutectic or near eutectic mixture of the fluorides of potassium, lithium and sodium; heating the bath to a temperature of about 1,000* to 1,400*F in a noncontaminating atmosphere; establishing in the bath a fluoborate ion concentration of approximately 2 to 5 percent, by weight and a titanium ion concentration of approximately 1-2 percent, by weight; purifying the bath by nonanodically introducing therein fine chips of elemental boron to react with contaminants therein; and establishing a current density at the cathode of 9-500 milliamperes per square centimeter, said current density being approximately 9-35 ma/cm2 at a temperature of 1,000*-1,100*F, 25-100 ma/cm2 at a temperature of 1,100*-1,250*F and 40-500 ma/cm2 at a temperature of 1,250*-1,400*F.

Claim 14

The process of claim 11 wherein the bath is purified prior to the establishment of the fluoborate concentration by subjecting the fluorides to a heat and vacuum treatment.