Controlled coefficient of thermal expansion vitreous enamel composition for electrosurgical tool

Patent metadata

Field	Value
Publication number	US-2019380767-A1
Application number	US-201716334233-A
Country	US
Kind code	A1
Filing date	Nov 14, 2017
Priority date	Nov 14, 2016
Publication date	Dec 19, 2019
Grant date	—

Abstract

A vitreous enamel coating for an electrosurgical metal cutting blade, the coating having a coefficient of thermal expansion substantially near the coefficient of thermal expansion of the metal cutting blade. Selection of materials having similar coefficients of thermal expansion results in an electrosurgical cutting blade with an improved insulating layer, substantially improved durability, or both.

First claim

1 . An article comprising:
(a) an electrosurgical cutting blade comprising a metal electrode having a coefficient of thermal expansion, and (b) a vitreous enamel coating on at least a portion of the metal electrode, the vitreous enamel coating having a coefficient of thermal expansion within less than ±30% of the metal electrode coefficient of thermal expansion.

2 - 4 . (canceled)

5 . The article of claim 1 , wherein the vitreous enamel has a dielectric strength of at least 20,000 volts/mm according to ASTM D149-09.

6 . The article of claim 1 , wherein the electrosurgical cutting blade exhibits a percent blade width reduction no lower than −12% according to the Blade Width Reduction Test.

7 . The article of claim 1 , wherein the vitreous enamel has a softening temperature of at least 500° C.

8 . The article of claim 1 , wherein the vitreous enamel has a softening temperature of at least 700° C.

9 . The article of claim 1 , wherein the vitreous enamel is an amorphous glass composition.

10 . The article of claim 1 , wherein the vitreous enamel is a glass-ceramic composition having a crystalline phase.

11 . The article of claim 0 , wherein the crystalline phase comprises Ca 2 ZnSi 2 O 7 or Sr 2 SiO 4 .

12 . The article of claim 1 , wherein the vitreous enamel comprises an aluminoborosilicate glass.

13 . The article of claim 1 , wherein the vitreous enamel is formed from a glass frit comprising SiO 2 , B 2 O 3 , Al 2 O 3 , and optionally one or more of SrO, BaO, CaO, MgO, ZnO, Na 2 O, K 2 O or a combination thereof.

9 . (canceled)

14 . (canceled)

15 . The article of claim 1 , wherein the vitreous enamel has a thickness of about 75 μm to about 100 μm.

16 . The article of claim 1 , wherein the vitreous enamel has a coefficient of thermal expansion of about 6×10 −6 /° C. to about 16×10 −6 /° C. according to ASTM E228.

17 . The article of claim 1 , wherein the vitreous enamel has a coefficient of thermal expansion of about 10×10 −6 /° C. to about 12×10 −6 /° C. according to ASTM E228.

18 . The article of claim 1 , wherein the metal electrode is titanium, tantalum, molybdenum, tungsten, stainless steel, or an alloy thereof.

19 . The article of claim 1 , wherein the metal electrode has a coefficient of thermal expansion of about 10×10 −6 /° C. to about 12×10 −6 /° C. according to ASTM E228.

20 . The article of claim 1 , wherein the vitreous enamel coating has a coefficient of thermal expansion within ±20% of the metal electrode coefficient of thermal expansion.

21 . The article of claim 1 , wherein the vitreous enamel coating has a coefficient of thermal expansion within ±10% of the metal electrode coefficient of thermal expansion.

22 . The article of claim 1 , wherein the vitreous enamel coating has a coefficient of thermal expansion less than the metal electrode coefficient of thermal expansion.

23 . The article of claim 1 , further comprising an insulated handle attached to the electrosurgical cutting blade and housing at least one conductor that can connect the metal electrode to a radiofrequency energy power supply.

24 . The article of claim 1 , wherein the vitreous enamel is formed from a glass frit comprising, as molar percentages:

SiO 2
 30-50%,

B 2 O 3
0.5-15%,

Al 2 O 3
0.5-10%,

SrO
  5-30%,

CaO
  5-30%, and

ZnO
0.5-20%.

Assignees

• Medtronic Advanced Energy Llc

Inventors

• Cheng Xiaoming
• Bhatt Himanshu K
• Huq Zahedul

Classifications

• C03C4/02

  for coloured glass · CPC title

• A61B2018/00083

  low, i.e. electrically insulating · CPC title

• C03C2204/00

  Glasses, glazes or enamels with special properties · CPC title

• C03C3/064

  containing boron · CPC title

• C03C10/00

  Devitrified glass ceramics, i.e. glass ceramics having a crystalline phase dispersed in a glassy phase and constituting at least 50% by weight of the total composition · CPC title