METHOD OF ACCURATE THICKNESS MEASUREMENT OF BORON CARBIDE COATING ON COPPER FOIL

• US 20160161416A1
• Filed: 11/12/2015
• Published: 06/09/2016
• Est. Priority Date: 11/12/2014
• Status: Active Grant

• Current Assignee: Proportional Technologies, Inc.
• Original Assignee: Proportional Technologies, Inc.
• Inventors: Lacy, Jeffrey L., Regmi, Murari
• Granted Patent: US 9,810,635 B2
• Time in Patent Office: Days
• CPC Class Codes: G01N 2021/8427 Coatings
• CPC Class Codes: G01N 21/68 using high frequency electric fields
• CPC Class Codes: G01N 21/73 using plasma burners or torches

Abstract

A method is disclosed of measuring the thickness of a thin coating on a substrate comprising dissolving the coating and substrate in a reagent and using the post-dissolution concentration of the coating in the reagent to calculate an effective thickness of the coating. The preferred method includes measuring non-conducting films on flexible and rough substrates, but other kinds of thin films can be measure by matching a reliable film-substrate dissolution technique. One preferred method includes determining the thickness of Boron Carbide films deposited on copper foil. The preferred method uses a standard technique known as inductively coupled plasma optical emission spectroscopy (ICPOES) to measure boron concentration in a liquid sample prepared by dissolving boron carbide films and the Copper substrates, preferably using a chemical etch known as ceric ammonium nitrate (CAN). Measured boron concentration values can then be calculated.

Claims

1. A process for measuring the effective thickness of a material coating on substrate comprising the steps of:

(1) removing a sample of the coated substrate from a larger length coated substrate;

(2) contacting the sample with an etching solution;

(3) allowing the etching solution to dissolve the sample;

(4) diluting the etching solution;

(5) determining the concentration of the material in the in the diluted etching solution; and

(6) calculating the effective thickness of the coating.

2. The process of claim 1, wherein the determining the concentration step comprises utilizing inductively coupled plasma optical emission spectroscopy to determine the concentration.

3. The process of claim 1, further comprising the step of weighing the sample of coated substrate after the removing step and before the contacting step.

4. The process of claim 1, wherein the removing a sample step comprises removing a sample at least about 1 square centimeter in size.

5. The process of claim 1, wherein the removing step comprises removing multiple samples from the substrate, the samples being taken at intervals of between about 50 and about 200 feet along the substrate.

6. The process of claim 1, wherein the material coating comprises a boron carbide coating.

7. A process for measuring the effective thickness of a boron carbide coating on copper foil comprising the steps of:

(1) removing a sample of the boron coated foil from a larger length of foil;

(2) contacting the sample with an etching solution;

(3) allowing the etching solution to dissolve the sample;

(4) diluting the etching solution;

(5) determining the concentration of boron carbide in the diluted etching solution; and

(6) calculating the effective thickness of the boron coating.

8. The process of claim 7 wherein the etching solution of the contacting step comprises a ceric ammonium nitrate solution.

9. The process of claim 8, wherein the ceric ammonium nitrate solution comprises between about 2 and about 25 percent by weight ceric ammonium nitrate.

10. The process of claim 8, wherein the ceric ammonium nitrate solution comprises between about 8 and about 10 percent by weight ceric ammonium nitrate.

11. The process of claim 7, wherein the diluting step comprises diluting the boron concentration to between about 2 and about 25 ppm.

12. The process of claim 7, wherein the determining the concentration step comprises determining the boron concentration to within about 0.1 ppm.

13. The process of claim 7, wherein the determining the concentration step comprises utilizing inductively coupled plasma optical emission spectroscopy to determine the concentration.

14. The process of claim 7, further comprising the step of weighing the sample of coated substrate after the removing step and before the contacting step.

15. The process of claim 7, wherein the removing a sample step comprises removing a sample at least about 1 square centimeter in size.

16. The process of claim 7, wherein the removing step comprises removing multiple samples from the substrate, the samples being taken at intervals of between about 50 and about 200 feet along the substrate.

17. A process for measuring the effective thickness of a boron carbide coating on copper foil comprising the steps of:

(1) removing a sample of the boron coated foil from a larger length of foil;

(2) weighing the sample of boron coated foil;

(3) contacting the sample with ceric ammonium nitrate etching solution;

(4) allowing the etching solution to dissolve the sample;

(5) diluting the etching solution;

(6) determining the concentration of boron carbide in the diluted etching solution using inductively coupled plasma optical emission spectroscopy; and

(7) calculating the effective thickness of the boron coating.