Esprit Rock



Hydroxyapatite HAP, (Ca10(PO4)6(OH)2 is a inorganic compound. It is widely used as bioactive coating material for orthopaedic applications due to its bioactivity, high biocompatibility, and as well as its good oseteoconductivity. The calcium phosphate material are wildly applied as biomaterial, adsorbents, catalyst, chemical engineering, and catalyst supports and mechanical reinforcement, etc…. Especially it is building block of human bone and dental. In this research the surface morphology and crystal structure of the novel synthesis of HAP nanoparticles are investigated the pre and post load shock wave. This method give hydroxyapatite powder a Nano size of particles and high degree of crystallinity. The Ca/p ratio is very nearest to the stoichiometry value (1:67). It was shown that synthesised hap powder result in high purity powder and crystallinity after a calcination. The as synthesised powder are to be tested further for this biocompatibility.

Hydroxyapatite has been one of the most important inorganic biomaterial. It has been widely applied in biomedical field due to biocompatibility, bioactivity, noninflammatory nature, and excellent osteoconductivity, and nontoxicity (1-3). HAP is a mineral form of Calcium phosphate and the formula of hap is (Ca10(PO4)6(OH)2. Calcium phosphate is one of the most widely investigated bio ceramic material and used clinically orthopaedic and dental aspects, such as bone filling and HAP used for artificial bone (4-5). It has been used in serval field, like dental implantology and biomedical application….and also used for electron spin resonance(ESR) (6). Calcium phosphate is the hydroxy apatite. This material is the promising material for implant and bone substitutes due to their biocompatibility, low density, chemical stability, and bio ceramic (7-9). The biological apatite refers to poorly crystalline nonstoichiometric carbonate containg HAP. The inorganic content varies from90% in dental and 65% in bones enamel (10). The pure HAP is a stoichiometric apatite phase, and it has a hexagonal structure. The Ca/P ratio of 1.67, which indicated to bone apatite. The most stable Ca/P salt at a normal temperature and PH between 4 to 12 (11). It has been reported that the synthesized hydroxyapatite nanoparticles is structurally and chemically to that of natural bone tissue (12-13). The interaction of material with shock heated gas leads to formation of new stabilization of material in new crystallography phase. The phase can be induced in material under temperature and extreme pressure due to application for a very short duration (14). The phase transformation of HAP nanoparticles using different shock wave number loading technique were employed to modified its structure.
In this research the surface morphology and crystal structure of the novel synthesis of HAP nanoparticles are investigated the pre and post load shock wave. The Characterized and structural feature of the hap powder were evolved by using FT-IR, XRD, SEM.
The novel synthesis of HAP nanoparticle’s by using shock wave method. They are Calcium nitrate tetrahydrate Ca(NO3)2 .4H2O, Diammonium hydrogen phosphate (NH3)2HPO4, and ammonium hydroxide NH4OH, were used. Deionized water was used throughout the synthetic process. All the received chemicals were of analyte grate(AR) and obtained from merk.
Pure HAP powder were synthesized under atmospheric conditions by using shock wave method. 0.5m Ca(NO3)2.4H2O and 0.3m (NH4)2HPO4 were dissolved into 100 ml of deionized water. The phosphate solution was added drop wise to the calcium solution by a constant stirring and we get white precipitate. Then the maintained PH between 9.5 to 10 by using ammonium solution. The stochiometric ratio of Ca/P was kept constant at 1.67 throughout the experiment. Now the sample is loaded at different number of shock wave like 50,100 with mech number 2.0 at applied pressure (2.367MPa) and temperature (896k). All the reaction kept in an oven at temperature 80oC for 4h. The obtained precipitate were filtered and washed three times by deionized water for the removal of residual ammonia and unreacted reactants followed by dried in an oven at 100oC for 3h. Finally the resulting powder were calcinated for 3 to 4hs and to obtain pure HAP. The received powder further characterized with different analytical techniques.

The Fourier transform infrared (FTIR) was used to determine the functional group of the hap sample. The spectra were recorded over the region of 400-4000 cm-1. The crystal structure and phase content of the sample were analysed by X-ray diffraction. The XRD was operated at 80kv and 10MA and the 2? range from 10 to 800C with a step size was 0.040. The crystallinity size of the sample can be calculated from XRD peak by using Scherrer equation. The SEM was use to investigated the morphology and size of the sample.
3.1 FTIF analysis of pure HAP powder
The FTIR spectra of HAP nanoparticle’s can be represent in fig.1. The hap structure contains OH and PO4 group. The broad band at 3410cm-1 and 1622cm-1 were due to the bending mode of the absorbed water while the sharp peak at 3570 cm-1 is stretching vibration of the lattice OH and the medium peak at 634 cm-1 cm-1 (OH) of hap. The band at 475 is indicated to the bending mode of PO4 group (?2). The peak at 1039-1085 cm-1 and 964 cm-1 correspond to the stretching vibration of PO4 group (?3 and ?1). The phosphate group appeared at two different wave number like 606 and 578 is due to the bending mode of PO4 group (?4).

The FTIR spectrum show in (Fif.2).The hap structure contains the OH broad peak at 3432 cm-1 and 1632 cm-1 are attributed to bending mode of absorb water and the medium peak at 625 cm-1. The band at 3580 cm-1 is represented by sharp peak of OH group. The ?1 and ?3 band of phosphate groups occur at 948 and 1086-1048 cm-1 respectively. The phosphate group was observed at 609 cm-1 and 578 cm-1 is corresponded to ?4. The peak at 484 cm-1 in can be assigned to ?2 mode

The FTIF spectrum (Fig.3) of the investigated powder show all characteristic peak of HAP. The sharp and broad peaks at 3580 cm-1 and 3419, 1652 cm-1 are corresponded to O-H groups and the medium band at 634 cm-1 OH of HAP. The peak at 465 cm-1 in can be indicated to ?2 mode of phosphate group and the band at 559 cm-1 and 606 cm-1 are due to ?4. The peaks at 954 cm-1 and 1086-2029 cm-1 are due to ?1 and ?3 mode of phosphate groups.

3.2. XRD Characterization of pure HAP powder
The powder diffraction and phase analyses were carried out by powder X-ray diffraction technique and a good correlation with stoichiometric hydroxyapatite. Fig.4 shows the XRD patterns of the synthesised HAP powder which are pure, the XRD patterns obtained of the hap sample. The XRD patterns of pre shock hap sample give sharp peak at 25.80, 31.68, 32,79, with (shock number 50) indicated the major peak at 25.87, 31,73, 32.86, and the peak at 25.86, 31.71, 32.86 can be indicated to sample with shock number 100. which were conformed the formation of hap. The pre shock wave loaded hap did not much differ from pure hap but slight change in grain size. The result are given in table.1. It is found that the XRD patterns of the hap sample are in good agreement with standard value of JCPDS data base () for hap which indicated that the crystal structure of hap sample is similar to the pure hydroxyapatite. The 50 hap showed lower crystallinity when compared to other hap. The crystallinity size of the sample can be calculated from XRD peak by using Scherrer equation.

S.NO SAMPLE 2?VALUE D grain size value (nm)
1 Shock number 50 25.87 43
31.73 28
32.78 28
2 Shock number 100 25.86 48
31.71 29
32.87 39
3 Controlled 25.80 49
31.68 33
32.79 41

The surface morphology and the size of the crystallinity of the synthesized hap powder were investigated by using scanning electron microscope. SEM image obtained for pure HAP nanoparticles were show in Fig (5). The particle size of HAP powder range from 20-30 nm with irregular shape. The image shows the hap particles are almost equal size and distribution. The formation of hydroxyapatite is conformed by SEM image.