硬化

1. Origins, structure, and basic meaning

• Structure: 硬化 is read as こうか and is a noun and する verb combining 硬 (hard) and 化 (change), meaning a material's hardening or solidification.
• Basic usage: Use 樹脂が硬化する for the material change and 寒さでゴムが硬化する for its cause.

2. Common pitfalls and similar expressions

• Curing and deterioration
  • Hardening may be an intended curing process for resin or harmful deterioration that makes rubber crack; context supplies the evaluation.
• Difference from 固まる
  • Everyday 固まる means become solid generally, while 硬化する is the more technical term for material, chemical, or industrial processes.