Optimizing sintering behavior and properties of gel-derived dental lithium disilicate glass-ceramics with HCl addition

Sintering behavior and properties of gel-derived lithium disilicate (Li 2 Si 2 O 5 , written as LD) glass-ceramics fabricated by traditional pressureless sintering were modified by HCl additives. HCl-modified powders showed hollow structure consisting of LD platelets, and more sintering necks initially formed by touching of LD platelets for as-sintered samples below 1010 ºC, along with LD crystals having larger size (width: 1.03–7.44 μm; length: 3.33–31.55 μm) at 1010 ºC. Correspondingly, HCl-free powders owned densified morphologies, and less sintering necks and LD crystals with smaller size (width: 2.05–7.72 μm; length: 3.51–17.78 μm) appeared. HCl-modified samples possessed higher relative densities (85.7 ± 1.9–93.9 ± 2.2 %), flexural strengths (86.1 ± 4.2–207.1 ± 4.8 MPa) and hardness (1.6 ± 0.1–4.9 ± 0.1 GPa) than HCl-free samples. Its flexural strength increased by 51 % than reported ones, and its Li + ions release ability was better. • A little HCl optimized sintering behavior of lithium disilicate glass-ceramic. • A little HCl decoupled microstructure control from reported seed-dependent method. • Both good mechanical properties and Li + ions release ability were acquired.