Enhancement of aluminum phosphate adhesion performance by nano-clay for terracotta figurine restoration

Constructing inorganic adhesive to bond the broken fragments that for that meet the requirements of restoration of cultural relics is still challenging. In response to this problem, a new design of nano-clay/aluminum phosphate adhesive and the preparation of corresponding material were proposed. An orthogonal experiment L25 (53)was conducted to optimize the ratio of the adhesives. The composite adhesive was characterized and the bonding efficiencies of mimicking terracotta figurine were evaluated. Based on the above experiments, the composite adhesive with attractive mechanical properties is mainly based on the Si–O–P, Al–O–P covalent bond and hydrogen bond interactions between nano-clay surface and aluminum phosphate. The proposed inorganic adhesive has advantages in similarity with the raw materials of the restored cultural relics, easy control of bonding course, durability, and environmental friendliness, which represents a potential utility of this adhesive in the restoration of earthenware relics.