Process for manufacturng a polychelate coating

Claim 2

A process for forming a stable, bonded, electrically conducting, polychelate coating on an electrically conductive substrate surface providing metal coordination centers therein which comprises: contacting said surface with a vaporized tetranitrile compound in amounts of not more than about 10 grams per square meter of said surface at temperatures between about 400° and 600° C. for a time period of between about 12 and about 24 hours and under conditions carefully controlled to avoid substantial thermal decomposition of said tetranitrile compound or other undesirable competing reactions, thereby achieving a cross-linked, relatively insoluble polychelate coating bonded to the substrate via said metal coordination centers.

Claim 3

The process of claim 1, characterized in that said substrate surface comprises an electrochemical valve metal or a valve metal alloy.

Claim 4

The process of claim 2, characterized in that the substrate comprises titanium.

Claim 5

The process of claim 1, 2 or 3 characterized in that the substrate surface is pretreated by heating under a vacuum of 10 -2 to 10 -3 Torr before contacting some with tetronitrile.

Claim 6

The process of claim 1 or 2, characterized in that said compound in the vapour phase is a cyclic tetranitrile compound.

Claim 7

The process according to any one of claims 1, characterized in that said tetranitrile compound is tetracyanobenzene, 550° being maximum temperature.

Claim 8

The process according to any one of claims 1, characterized in that said tetranitrile compound is tetracyanoethylene.

Claim 9

The process of claim 1, characterized in that the specific amount of tetranitrile compound provided in the vapour phase per unit area of the substrate surface is at least 1 g/m 2 .

Claim 10

The process of claim 8, characterized in that the substrate body comprises at least one metal selected from the group consisting of cobalt, iron, nickel, copper and aluminium, or an alloy thereof.

Claim 11

The process of claim 9, characterized in that said specific amount of tetranitrile compound is selected from the range between 5 and 10 g/m 2 .

Claim 12

The process of claim 1, characterized in that the substrate is pretreated by sandblasting before contacting some with tetronitrile.

Claim 13

The process of claim 1, characterized in that said substrate surface comprises a platinum-group metal providing metal coordination sites for said heterogeneous in situ vapor phase reaction.

Claim 14

A process for manufacturing a stable, electrically conducting polychelate coating formed on an electrically conducting substrate body by carrying out a heterogeneous chelating reaction between a tetranitrile compound vapor and metal coordination centers on the surface of the substrate body, characterized in that: (a) a controlled chelating reaction is carried out by bringing the substrate body into contact with tetracyanobenzene vapor in a restricted specific amount (X o ) at most equal to 10 g/m 2 of said surface of the substrate body, so as to thereby allow substantially complete chelation of this restricted amount (X o ) by means of the metal on said surface, and by carrying out the chelating reaction at a temperature between 400° C. and 550° C., so as to convert this restricted amount of tetracyanobenzene into a corresponding chelate coating in a restricted amount (X) sufficient to provide substantially complete chelation throughout this coating; (b) the chelate coating produced by the controlled reaction in step (a) is subjected to a controlled thermal treatment at a temperature between 400° C. and 550° C. so as to convert this chelate coating into a corresponding polychelate and to thereby produce a stable, insoluble, electrically conducting poly-chelate coating formed and bonded to said substrate surface by means of said metal coordination centers provided by the substrate body; and

Claim 15

A process for manufacturing a stable, electrically conducting polychelate coating formed on an electrically conducting substrate body by carrying out a heterogeneous chelating reaction between a tetranitrile compound vapor and metal coordination centers on the surface of the substrate body, characterized in that: (a) a controlled chelating reaction is carried out by bringing the substrate body into contact with tetracyanobenzene vapor in a restricted specific amount (X o ) at most equal to 10 g/m 2 of said surface of the substrate body, so as to thereby allow substantially complete chelation of this restricted amount (X o ) by means of the metal on said surface, and by carrying out the chelating reaction at a temperature between 400° C. and 550° C., so as to convert this restricted amount of tetracyanobenzene into a corresponding chelate coating in a restricted amount (X) sufficient to provide substantially complete chelation throughout this coating; (b) the chelate coating produced by the controlled reaction in step (a) is subjected to a controlled thermal treatment at a temperature between 400° C. and 550° C. so as to convert this chelate coating into a corresponding polychelate and to thereby produce a stable, insoluble, electrically conducting poly-chelate coating formed and bonded to said substrate surface by means of said metal coordination centers provided by the substrate body; and

Claim 16

(c) said chelating reaction (a) and said thermal treatment (b) being carried out in 12 to 24 hours so as to provide substantially insoluble and well bonded polychelate coating, while avoiding thermal decomposition of said chelate or said polychelate.

Claim 17

(c) said chelating reaction (a) and said thermal treatment (b) being carried out in 12 to 24 hours so as to provide substantially insoluble and well bonded polychelate coating, while avoiding thermal decomposition of said chelate or said polychelate.

Claim 18

The process of claims 10, 1 or 13 wherein the substrate comprises nickel or a nickel alloy.

Claim 19

The process of claim 14, characterized in that the substrate surface is pretreated with a base, preferably sodium hydroxide.

Claim 20

The process of claim 10, 1 or 13 wherein the substrate comprises iron or an iron alloy.

Claim 21

A process for manufacturing a stable, electrically conducting polychelate coating formed on an electrically conducting substrate body by carrying out a heterogeneous chelating reaction between a tetranitrile compound vapor and metal coordination centers on the surface of the substrate body, characterized in that: (a) a controlled chelating reaction is carried out by bringing the substrate body into contact with tetracyanoethylene vapor in a restricted specific amount (X o ) at most equal to 10 g/m 2 of said surface of the substrate body, so as to thereby allow substantially complete chelation of this restricted amount (X o ) by means of the chelating metal on said surface, and by carrying out the chelating reaction at a temperature between 400° C. and 600° C., so as to convert this restricted amount of tetracyanoethylene into a corresponding chelate coating in a restricted amount (X) sufficient to provide substantially complete chelation throughout this coating; (b) the chelate coating performed by the controlled reaction in step (a) is subjected to a controlled thermal treatment at a temperature between 400° C. and 600° C., so as to convert this chelate coating into a corresponding polychelate and to thereby produce stable, insoluble, electrically conducting poly-chelate coating formed and bonded to said substrate surface by means of said metal coordination centers provided by the substrate body; and (c) said chelating reaction (a) and said thermal treatment (b) being carried out in 12 to 24 hours so as to provide substantially insoluble and well bonded polychelate coating, while avoiding thermal decomposition of said chelate or said polychelate.

Claim 22

A process for manufacturing a stable, electrically conducting polychelate coating formed on an electrically conducting substrate body by carrying out a heterogeneous chelating reaction between a tetranitrile compound vapor and metal coordination centers on the surface of the substrate body, characterized in that: (a) a controlled chelating reaction is carried out by bringing the substrate body into contact with tetracyanoethylene vapor in a restricted specific amount (X o ) at most equal to 10 g/m 2 of said surface of the substrate body, so as to thereby allow substantially complete chelation of this restricted amount (X o ) by means of the chelating metal on said surface, and by carrying out the chelating reaction at a temperature between 400° C. and 600° C., so as to convert this restricted amount of tetracyanoethylene into a corresponding chelate coating in a restricted amount (X) sufficient to provide substantially complete chelation throughout this coating; (b) the chelate coating performed by the controlled reaction in step (a) is subjected to a controlled thermal treatment at a temperature between 400° C. and 600° C., so as to convert this chelate coating into a corresponding polychelate and to thereby produce stable, insoluble, electrically conducting poly-chelate coating formed and bonded to said substrate surface by means of said metal coordination centers provided by the substrate body; and (c) said chelating reaction (a) and said thermal treatment (b) being carried out in 12 to 24 hours so as to provide substantially insoluble and well bonded polychelate coating, while avoiding thermal decomposition of said chelate or said polychelate.

Claim 23

The process of claim 13 or 17, characterized in that the substrate body and said restricted specific amount (X o ) of the tetranitrile compound in solid form are placed in a vessel which is evacuated to a vacuum of about 10 -2 to 10 -3 Torr, sealed and then heated so as to carry out said controlled heterogeneous in either vapor phase reaction and thermal treatment.

Claim 24

The process of claim 13 or 17, characterized in that a catalytic outer coating is further applied onto said polychelate coating.

Claim 25

The process of claim 19, characterized in that said catalytic coating comprises a platinum-group metal.

Claim 26

The process of claim 13 or 17, characterized in that said chelating reaction and said thermal treatment are carried out in a protective atmosphere to prevent oxidation of said coating or surface.