Silicon nitride glow plugs are compounds synthesized under artificial conditions. Although silicon nitride was directly synthesized more than 140 years ago, it remained in people's memory as a stable "refractory" nitride.
After the Second World War, the development of science and technology urgently needed materials with high hardness and corrosion resistance.
After long-term efforts, silicon nitride was not valued until 1955, and high-quality, important-purpose silicon nitride ceramic products were produced in the mid-70s. my country has been studying silicon nitride since the mid-1980s. It is mainly to study the structural silicon nitride material-porous silicon nitride material for weight reduction efficiency. The research on silicon nitride composite materials has just started, and there are few researches on the theoretical design and experimental design of the porous silicon nitride composite material composition system. It is still in the exploratory stage and is affected by relatively few external correlations. In this regard, my country's research has been relatively backward. Many research units and scholars have focused their research in the military industry, while applied research in other fields is basically blank. Research in this area needs to be further strengthened. The prediction of the dielectric constant of porous silicon nitride ceramics and the influence of its properties are not well understood, and there are few researches on its theoretical work and experimental work. As environmental climate change and energy shortage have become issues that all countries in the world need to face together, heat pump water heaters, as an energy-saving product, are in the ascendant in the market. Compared with hot water products such as boilers, gas water heaters, electric water heaters and solar water heaters, heat pump water heaters have an energy efficiency ratio (COP) of 3.0 to 4.5, which is energy-saving, comfortable, stable, and low-cost.
