"The armored playing grants the golem wearing it increased resistance to physical harm. Unfortunately the additional protection comes at a cost, as all the heavy ironmongery will slow it down." - Thaumonomicon Entry
Golem iron plating is an accessory that can be equipped onto golems.
It significantly increases defense but greatly lowers speed, making it not recommended for farming/fishing/gathering golems.
For the aspects you'll need 8 Terra