One common way to reduce sintering temperatures is to increase the driving force of densification through applying pressure simultaneously with temperature, such as overpressure sintering [8] , hot pressing [9,10], and hot isostatic pressing [11,12]. Another approach is through utilizingelectrical field to enhance diffusion processes, such as flash sintering [13,14], spark plasma sintering [15,16], and microwave sintering [17,18]. Even though the sintering temperature has been reduced to some extent, it is still quite high [19–24].