Title

Implanting Compound Y Into Existing Ceramic Varistor Formulations: Ceramics Processing and Temperature Dependence of Grains

Author(s)

Sahil MongaFollow

School Name

South Carolina Governor's School for Science & Mathematics

Grade Level

12th Grade

Presentation Topic

Engineering

Presentation Type

Mentored

Abstract

A varistor is an electrical component commonly used in surge protection. Varistors are placed in parallel to the main circuit and have a high resistance until a power surge triggers resistance to drop most of the high allowing current to flow through the varistor rather than the main circuit. The objective of this research was to create a cost-effective varistor that performed better than existing varistors in degradation testing. This would be achieved by mixing Compound Y, which although expensive has good degradation properties, with Compound X, a compound commonly used for its cost-effectiveness. Although the research was conducted in an industrial setting, the processes were catered towards small scale production. Steps like grinding were performed with a mortar and pestle and pellets were pressed using a uniaxial die press. Various tests were conducted to analyze aspects of this new varistor. SEM (Scanning Electron Microscopy) provides a closer look at the grain structure of a varistor. By calculating the average grain size, the breakdown voltage could be predicted even before voltage was applied to the varistor. This part of the research focuses more on grain size trends as well as evaluation of the grain structures of the varistors. For compositions containing compound X, they did much better from 1050°C - 1100°C; the composition with only Y fired better at >1300°C. The trends displayed by grain size confirmed our initial hypotheses: grain size will increase with temperature, and the higher the weight percent of Y, the smaller the grain size.

Location

Johns Hall 109

Start Date

3-28-2020 11:00 AM

Presentation Format

Oral Only

Group Project

No

COinS
 
Mar 28th, 11:00 AM

Implanting Compound Y Into Existing Ceramic Varistor Formulations: Ceramics Processing and Temperature Dependence of Grains

Johns Hall 109

A varistor is an electrical component commonly used in surge protection. Varistors are placed in parallel to the main circuit and have a high resistance until a power surge triggers resistance to drop most of the high allowing current to flow through the varistor rather than the main circuit. The objective of this research was to create a cost-effective varistor that performed better than existing varistors in degradation testing. This would be achieved by mixing Compound Y, which although expensive has good degradation properties, with Compound X, a compound commonly used for its cost-effectiveness. Although the research was conducted in an industrial setting, the processes were catered towards small scale production. Steps like grinding were performed with a mortar and pestle and pellets were pressed using a uniaxial die press. Various tests were conducted to analyze aspects of this new varistor. SEM (Scanning Electron Microscopy) provides a closer look at the grain structure of a varistor. By calculating the average grain size, the breakdown voltage could be predicted even before voltage was applied to the varistor. This part of the research focuses more on grain size trends as well as evaluation of the grain structures of the varistors. For compositions containing compound X, they did much better from 1050°C - 1100°C; the composition with only Y fired better at >1300°C. The trends displayed by grain size confirmed our initial hypotheses: grain size will increase with temperature, and the higher the weight percent of Y, the smaller the grain size.