ISO 11245 pdf download

ISO 11245 pdf download.Dental restorations — Phosphate-bonded refractory die materials 1 Scope This International Standard is applicable to phosphate bonded refractory die materials used in the production of dental restorations by a sintering technique. It specifies requirements for the essential physical properties of the refractory die material and the test methods to be used to determine these properties. It also includes a requirement for adequate instructions to accompany each package. 2 Terms and definitions For the purposes of this International Standard, the following terms and definitions apply. 2.1 refractory die material powder mixture of a refractory filler system and a binding system specially designed so that when mixed with a liquid it forms a hardened die suitable for the production of dental ceramic restorations using the sintering technique NOTE The refractory filler system usually consists of refractory oxides such as silica. The binding system usually consists mainly of an acidic phosphate such as ammonium dihydrogenphosphate together with a basic oxide such as magnesium oxide. When the mixture is mixed with a suitable liquid it forms a paste that hardens at room temperature to form a refractory die. The suitable liquid may be the special liquid (2.2), the special liquid diluted with water, or it can be water alone. 2.2 special liquid liquid made available by the manufacturer or supplier for mixing with the powder mixture NOTE The special liquid usually consists mainly of a suspension of colloidal silica particles in water. 3 Requirements 3.1 Quality The powder (2.1 ) shall be uniform and free from foreign matter and lumps when examined visually. If a special liquid (2.2) is required, it shall be free of sediment. 3.2 Fluidity The diameter of the base of the set mass shall be at least 70 mm. Test in accordance with 5.1 . 3.3 Setting time The setting time shall not differ by more than 30 % from the time stated by the manufacturer. If the manufacturer gives a range of setting time.3.4 Compressive strength The compressive strength of the set refractory die material shall be not less than 1 3 MPa. Test in accordance with 5.3 and report in accordance with 6 j). 3.5 Linear setting expansion For the reasons stated in Introduction, the linear setting expansion requirement shall be as specified in clause A.1 of annex A. 3.6 Linear thermal dimensional change The linear dimensional change after firing (degassing) and the linear thermal...