This chapter focuses on two topics for a green manufacturing approach to silicon nitride ceramic components. One is a sintered reaction bonding process with rapid nitridation. The particular focus is on the rapid nitridation of silicon powder enhanced by zirconia addition, which leads to significant energy savings, and resultant sintered-reaction-bonded silicon nitride ceramics. Good mechanical properties equivalent to those of gas-pressure sintered material from high-purity silicon nitride powder can be obtained via sintered reaction bonding technique with rapid nitridation using silicon powder, whenever the fabrication process is optimized. The other topic is low-temperature sintering of silicon nitride, below 1700. °C, with atmospheric pressure. It is revealed that β-phase powder showed better sinterability than α-phase one at such low temperatures, and the sintered bodies showed relatively moderate mechanical properties, which are acceptable depending on the application. Combining the low-temperature sintering and the use of low-cost β powder is advantageous for saving energy in the sintering process of silicon nitride components, as well as reducing the production cost.