ART
BEAUTY & WELLNESS
CRAFT
CULTURE & HISTORY
ENTERTAINMENT
ENVIRONMENT
FOOD & DRINKS
REVERSE ENGINEERING
SCIENCES
SPORTS
TECHNOLOGY
WEARABLES
Metal Oxide Varistor: Zinc Oxide with 0.2 % Aluminium Oxide, Bismuth Oxide Paste Fired On (Masuyama 1972, Ex. 5)
A varistor with bismuth oxide fired on from a paste instead of mixed in: 99.8 % zinc oxide with 0.2 % aluminium oxide by moles, sintered at 1350 °C, coated with bismuth oxide paste and fired at 800 °C. The disc measured a C-value of 46 at 1 mA and a nonlinearity exponent n of 5.6.
Source: T. Masuyama, M. Matsuoka and T. Nishi (Matsushita), US 3,663,458 (1972), Example 5. Unknown: how the aluminium is sprayed on, what the silver paint is, and how strong the epoxy solution of the paste is. The 10 g batch is our arithmetic. Picture: the patent's drawing.
Advanced
2 days
Instructions
1
1
Weigh 99.8 : 0.2 and wet-mill 5 hours
Weigh 99.8 : 0.2 and wet-mill 5 hours
Mix zinc oxide and aluminium oxide 99.8 : 0.2 by moles. Ours, for 10 g: 9.975 g zinc oxide and 0.025 g aluminium oxide (our arithmetic). Mill wet for 5 hours, then dry, as in Example 1. Unknown: the milling liquid.
Materials for this step:
Zinc Oxide Powder9.975 g
Alumina Powder (Aluminium Oxide)0.025 gTools needed:
Balance Scale
Iron Ball Mill
Drying Oven2
2
Press discs 13 mm by 2.5 mm
Press discs 13 mm by 2.5 mm
Press discs 13 mm across and 2.5 mm thick at 340 kg/cm², as in Example 1.
Tools needed:
Hydraulic Press
Disc Pressing Die
Vernier Caliper3
3
Sinter 1 hour at 1350 °C and furnace-cool
Sinter 1 hour at 1350 °C and furnace-cool
As in Example 2: sinter in air at 1350 °C for 1 hour and let the discs cool in the furnace.
Tools needed:
Muffle Furnace4
4
Lap both faces
Lap both faces
Lap both faces with silicon carbide abrasive. Example 5 gives no thickness.
Tools needed:
Silicon Carbide GritVernier Caliper5
5
Coat with bismuth oxide paste and fire at 800 °C
Coat with bismuth oxide paste and fire at 800 °C
Coat both lapped faces with a paste of 50 % by weight bismuth oxide in a solution of epoxy resin in butyl alcohol, and fire it in air at 800 °C for 30 minutes. The bismuth oxide diffuses into the zinc oxide. Not given: how much paste, or the strength of the epoxy solution.
Materials for this step:
Bismuth Oxide1 as requiredTools needed:
Epoxy Resin
n-ButanolMuffle Furnace6
6
Spray aluminium electrodes and attach leads
Spray aluminium electrodes and attach leads
Spray a metallised film of aluminium on both faces. Attach a lead wire to each with conductive silver paint, as in Example 1. Unknown: the spraying method and the paint.
Materials for this step:
Aluminium Ingot1 as required
Silver Conductive Paint1 as required
Copper Wire2 piecesTools needed:
Unknown Metal Spraying MethodVernier CaliperMaterials
6- 9.975 gPlaceholder
- Placeholder
- 1 as requiredPlaceholder
- 1 as requiredPlaceholder
- 1 as requiredPlaceholder
- 2 piecesPlaceholder
Tools Required
11- Placeholder
- Placeholder
- Placeholder
- Placeholder
- Placeholder
- Placeholder
- Placeholder
- Placeholder
- Placeholder
- Placeholder
- Placeholder
This blueprint makes
Related Blueprints
These blueprints share knowledge with this one — techniques, materials, or principles that connect them in the learning graph.
CC0 Public Domain
This blueprint is released under CC0. You are free to copy, modify, distribute, and use this work for any purpose, without asking permission.
Support the Maker by purchasing products through their Blueprint where they earn a Maker Commission set by Vendors, or create a new iteration of this Blueprint and include it as a connection in your own Blueprint to share revenue.