ASTM F204-76(1996)e1

Standard Test Method for Surface Flaws in Tungsten Seal Rod and Wire

SCOPE
1.1 This test method covers the determination of the presence of surface flaws in tungsten-seal rod and wire of random or cut lengths, and in the tungsten section of multiple-piece-through leads used in electronic devices, by means of examination of a glass bead sealed to the tungsten.
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 25-Nov-1976
• Technical Committee: F01 - Electronics
• Drafting Committee: F01.03 - Metallic Materials, Wire Bonding, and Flip Chip

Relations

• Replaced By: ASTM F204-76(2002) - Standard Test Method for Surface Flaws in Tungsten Seal Rod and Wire
• Effective Date: 26-Nov-1976
• Referred By: ASTM F288-96(2019) - Standard Specification for Tungsten Wire for Electron Devices and Lamps
• Effective Date: 26-Nov-1976

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
e1
Designation: F 204 – 76 (Reapproved 1996)
Standard Test Method for
Surface Flaws in Tungsten Seal Rod and Wire
This standard is issued under the fixed designation F 204; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
e NOTE—Keywords were added editorially in June 1996.
1. Scope 4. Preparation of Test Specimen
1.1 This test method covers the determination of the pres- 4.1 The test specimen shall be a beaded tungsten rod
ence of surface flaws in tungsten-seal rod and wire of random prepared in the following manner:
or cut lengths, and in the tungsten section of multiple-piece- 4.1.1 Clean the surface to be beaded in the usual manner
through leads used in electronic devices, by means of exami- employed by the user of the tungsten.
nation of a glass bead sealed to the tungsten. 4.1.2 Alternative Methods of Specimen Preparation—In
1.2 This standard does not purport to address all of the case of disagreement between the manufacturer and the pur-
safety concerns, if any, associated with its use. It is the chaser, substitute one of the following alternative methods of
responsibility of the user of this standard to establish appro- preparing the tungsten rod for that in 4.1.1.
priate safety and health practices and determine the applica- 4.1.2.1 Boil the tungsten for 2 min in a 5 % solution of 27 %
bility of regulatory limitations prior to use. hydrogen peroxide. Pour off the hydrogen peroxide and rinse
the tungsten twice in distilled water. Dry rapidly with pure
2. Terminology
alcohol or in an oven heated to 100°C.
2.1 Definitions:
4.1.2.2 Place the tungsten in a solution (20 weight %) of
2.1.1 beaded length—the actual length through which a sodium hydroxide or potassium hydroxide and pass sufficient
glass-to-tungsten seal exists as evidenced by the color of the
electrical current through it to induce electrolytic action
interface. sufficient to clean the specimen.
2.1.2 fault—a tungsten-glass seal in which a fissure, either
4.2 Bead the cleaned tungsten rod over the area to be
delineated by a line of bubbles or in itself clearly discernible, examined with glass, of the type and wall thickness commonly
is observed when inspected as prescribed in this test method.
used for beading, to a length of not less than 5 mm bead length.
2.1.3 fissure—any narrow opening or cleft in the surface of 4.3 To permit examination of the glass-tungsten interface,
the tungsten.
the bead shall be substantially free from bubbles, from causes
2.1.4 line of bubbles—one long or several small bubbles so other than the tungsten defects, and shall have been so prepared
arranged in the otherwise substantially bubble-free glass bead
that the surface of the tungsten is clearly visible through the
that they are in an almost straight line immediately adjacent to
bead.
the tungsten-glass interface. 4.4 The color of the glass
...